Three-dimensional printing

ABSTRACT

This disclosure describes compositions, kits, methods, systems, and three-dimensional parts. According to an example, described herein is a method of forming a polymeric powder build material composition for three-dimensional printing, the method comprising mixing a thermoplastic polymer powder composition, antioxidants, flow aids, a surface modifying agent, antistatic agents, and filler.

BACKGROUND

Three-dimensional (3D) printing may be an additive printing process usedto make three-dimensional solid parts from a digital model. 3D printingis often used in rapid product prototyping, mold generation, mold mastergeneration, and short run manufacturing. Some 3D printing techniques areconsidered additive processes because they involve the application ofsuccessive layers of material (which, in some examples, may includebuild material, binder and/or other printing liquid(s), or combinationsthereof). This is unlike traditional machining processes, which oftenrely upon the removal of material to create the final part. Some 3Dprinting methods use chemical binders or adhesives to bind buildmaterials together. Other 3D printing methods involve at least partialcuring, thermal merging/fusing, melting, sintering, etc. of the buildmaterial, and the mechanism for material coalescence may depend upon thetype of build material used. For some materials, at least partialmelting may be accomplished using heat-assisted extrusion, and for someother materials (e.g., polymerizable materials), curing or fusing may beaccomplished using, for example, ultra-violet light or infrared light.

BRIEF DESCRIPTION OF THE DRAWINGS

Features of examples of the present disclosure will become apparent byreference to the following detailed description and drawings, in whichlike reference numerals correspond to similar, though perhaps notidentical, components. For the sake of brevity, reference numerals orfeatures having a previously described function may or may not bedescribed in connection with other drawings in which they appear.

FIG. 1 is a flow diagram illustrating an example of a method of forminga build material composition for three-dimensional printing;

FIG. 2 is a flow diagram illustrating an example of a method forthree-dimensional printing;

FIGS. 3A through 3E are schematic and partially cross-sectional cutawayviews depicting the formation of a 3D part using an example of the 3Dprinting method disclosed herein;

FIG. 4 is a simplified isometric and schematic view of an example of a3D printing system disclosed herein; and

FIG. 5 is a flow diagram illustrating an example of a method of forminga three-dimensional printed part.

DETAILED DESCRIPTION

Some examples of three-dimensional (3D) printing may utilize a fusingagent (including a radiation absorber) to pattern polymer buildmaterial. In these examples, an entire layer of the polymer buildmaterial is exposed to radiation, but the patterned region (which, insome instances, is less than the entire layer) of the polymer buildmaterial is fused/coalesced and hardened to become a layer of a 3D part.

In the patterned region, the fusing agent is capable of at leastpartially penetrating into voids between the polymer build materialparticles, and is also capable of spreading onto the exterior surface ofthe polymeric build material particles. This fusing agent is capable ofabsorbing radiation and converting the absorbed radiation to thermalenergy, which in turn fuses/coalesces the polymer build material that isin contact with the fusing agent. Fusing/coalescing causes the polymerbuild material to join or blend to form a single entity (i.e., the layerof the 3D part). Fusing/coalescing may involve at least partial thermalmerging, melting, binding, and/or some other mechanism that coalescesthe polymer build material to form the layer of the 3D part.

As used herein, “material set” or “kit” is understood to be synonymouswith “composition.” Further, “material set” and “kit” are understood tobe compositions comprising one or more components where the differentcomponents in the compositions are each contained in one or morecontainers, separately or in any combination, prior to and duringprinting but these components can be combined together during printing.The containers can be any type of a vessel, box, or receptacle made ofany material.

As used herein, “(s)” at the end of some terms indicates that thoseterms/phrases may be singular in some examples or plural in someexamples. It is to be understood that the terms without “(s)” may bealso be used singularly or plurally in many examples.

Compositions/Kits

Disclosed herein is an example of a three-dimensional printingcomposition comprising: a polymeric powder build material comprising athermoplastic polymer powder composition, wherein the thermoplasticpolymer powder composition comprises: (a) at least 50 wt % of a C3polyolefin, or a mixture of two or more polyolefins including at least60 wt % of a C3 polyolefin based on the total weight of the mixture ofthe two or more polyolefins, based on the total weight of thethermoplastic polymer powder composition, (b) 0.1 to 1 wt % antioxidantsbased on the total weight of the thermoplastic polymer powdercomposition, (c) 0.1 to 5 wt % flow aids based on the total weight ofthe thermoplastic polymer powder composition, (d) 0-10 wt % of a surfacemodifying agent based on the total weight of the thermoplastic polymerpowder composition, (e) 0.05-wt %-10 wt % antistatic agents based on thetotal weight of the thermoplastic polymer powder composition, (f) 2 wt %to 40 wt % filler based on the total weight of the thermoplastic polymerpowder composition, wherein the total of (a) to (f) is 100 wt %.

The three-dimensional printing composition can further comprise: afusing agent comprising at least one infrared absorbing compound.

The three-dimensional printing composition can further comprise: adetailing agent comprising at least at least 50 wt % water based on thetotal weight of the detailing agent.

The surface modifying agent can be present in an amount of from about0.2 wt % to about 5 wt % based on the total weight of the thermoplasticpolymer powder composition.

The C3 polyolefin can be a polypropylene block copolymer.

The thermoplastic polymer powder composition can consist of apolypropylene block copolymer.

The filler can be a filler is a reinforcing material selected from thegroup consisting of glass beads, fumed silica, hollow glass beads, glassfibers, crushed glass, silicon dioxide, aluminum oxide, calciumcarbonate, hydrous aluminum silicate, ceramic fibers, silicon carbidefibers, alumina fibers, carbon fibers, polypropylene fibers, polyamidefibers, polyoxymethylene fibers, ultra-high molecular weightpolyethylene fibers, polytetrafluoroethylene fibers, liquid crystalfibers, aramid (e.g., Kevlar®) fibers, and combinations thereof.

The filler can be a flame retarding compound selected from the groupconsisting of an alkali or earth alkali sulfonate, sulphonamide salt,perfluoroborate, halogenated compound and phosphorus-bearing organiccompound, and combinations thereof.

The filler can be an elastomeric material selected from the groupconsisting of styrene butadiene styrene block copolymers,styrene-ethylene/butylene-styrene block copolymer,styrene-isoprene-styrene block copolymer, hydrogenatedstyrene-isoprene-styrene block copolymer, ethylene-propylene rubber,ethylene propylene diene monomer rubber, and combinations thereof.

Disclosed herein is an example of a method of using thethree-dimensional printing composition described above comprising:depositing a layer of the polymeric powder build material on a buildplatform.

Disclosed herein is an example of a composition for a three-dimensionalobject, the composition comprising: a polymeric powder build materialcomprising (a) a thermoplastic polymer powder composition, wherein thethermoplastic polymer powder composition comprises a polypropylene blockcopolymer made from polymerizing propylene and ethylene or butylene andpolypropylene homopolymers; a fusing agent comprising at least oneinfrared absorbing compound; and a detailing agent comprising at leastat least 60 wt % water based on the total weight of the detailing agent.

The polymeric powder build material can further comprise: (b) 0.1 to 1wt % antioxidants based on the total weight of the thermoplastic polymerpowder composition, (c) 0.1 to 5 wt % flow aids based on the totalweight of the thermoplastic polymer powder composition, (d) 0.2-5 wt %of a surface modifying agent based on the total weight of thethermoplastic polymer powder composition, (e) 0.05-wt %-5 wt %antistatic agents based on the total weight of the thermoplastic polymerpowder composition, (f) 10 wt % to 20 wt % filler based on the totalweight of the thermoplastic polymer powder composition, wherein thetotal of (a) to (f) is 100 wt %.

The polypropylene block copolymer can comprise the following particlesize distribution: D10: about 20 μm-about 45 μm; D50: about 50 μm-about85 μm; and D90: about 90 μm-about 140 μm.

The polypropylene block copolymer can have a melting peak temperature ofbetween about 130° C. and about 140° C.

The polypropylene block copolymer can have a crystallization peaktemperature of between about 98° C. and about 104° C.

The polypropylene block copolymer can have a melt flow index of at leastabout 4 g/10 min at about 190° C.

Disclosed herein is an example of a three-dimensional printing kitcomprising: a polymeric powder build material comprising a thermoplasticpolymer powder composition, wherein the thermoplastic polymer powdercomposition comprises a polypropylene block copolymer made frompolymerizing propylene and ethylene or butylene and polypropylenehomopolymers; a fusing agent comprising at least one infrared absorbingcompound; and a detailing agent comprising at least 70 wt % water basedon the total weight of the detailing agent, wherein the polymeric powderbuild material, the fusing agent, and the detailing agent are eachhoused in separate containers.

Methods

Disclosed herein is an example of a method of forming a polymeric powderbuild material composition for three-dimensional printing, the methodcomprising: mixing (A) a thermoplastic polymer powder compositioncomprising: at least 50 wt % of a C3 polyolefin, or a mixture of two ormore polyolefins including at least 60 wt % of a C3 polyolefin based onthe total weight of the mixture of the two or more polyolefins, based onthe total weight of the thermoplastic polymer powder composition, (B)0.1 to 1 wt % antioxidants based on the total weight of thethermoplastic polymer powder composition, (C) 0.1 to 5 wt % flow aidsbased on the total weight of the thermoplastic polymer powdercomposition, (D) 0-10 wt % of a surface modifying agent based on thetotal weight of the thermoplastic polymer powder composition, (E)0.05-wt %-10 wt % antistatic agents based on the total weight of thethermoplastic polymer powder composition, (F) 2 wt % to 40 wt % fillerbased on the total weight of the thermoplastic polymer powdercomposition, wherein the total of (A) to (F) is 100 wt %, to form thepolymeric powder build material composition.

The surface modifying agent can be present in an amount of from about0.2 wt % to about 5 wt % based on the total weight of the thermoplasticpolymer powder composition.

The C3 polyolefin can be a polypropylene block copolymer.

The thermoplastic polymer powder composition can consist of apolypropylene block copolymer.

The filler can be a filler is a reinforcing material selected from thegroup consisting of glass beads, fumed silica, hollow glass beads, glassfibers, crushed glass, silicon dioxide, aluminum oxide, calciumcarbonate, hydrous aluminum silicate, ceramic fibers, silicon carbidefibers, alumina fibers, carbon fibers, polypropylene fibers, polyamidefibers, polyoxymethylene fibers, ultra-high molecular weightpolyethylene fibers, polytetrafluoroethylene fibers, liquid crystalfibers, aramid (e.g., Kevlar®) fibers, and combinations thereof.

The filler can be a flame retarding compound selected from the groupconsisting of an alkali or earth alkali sulfonate, sulphonamide salt,perfluoroborate, halogenated compound and phosphorus-bearing organiccompound, and combinations thereof.

The filler can be an elastomeric material selected from the groupconsisting of styrene butadiene styrene block copolymers,styrene-ethylene/butylene-styrene block copolymer,styrene-isoprene-styrene block copolymer, hydrogenatedstyrene-isoprene-styrene block copolymer, ethylene-propylene rubber,ethylene propylene diene monomer rubber, and combinations thereof.

Disclosed herein is an example of a method of using the polymeric powderbuild material composition described above comprising: depositing alayer of the polymeric powder build material on a build platform.

Disclosed herein is an example of a method for three-dimensionalprinting comprising: depositing a layer of a polymeric powder buildmaterial on a build platform, the polymeric powder build materialcomprising (A) a thermoplastic polymer powder composition, wherein thethermoplastic polymer powder composition comprises a polypropylene blockcopolymer made from polymerizing propylene and ethylene or butylene andpolypropylene homopolymers; based on a 3D object model, selectivelyapplying a fusing agent to at least a portion of the layer of thepolymeric powder build material, wherein the fusing agent comprises atleast one infrared absorbing compound; and exposing the build materialcomposition to radiation to fuse the at least the portion to form alayer of a 3D part.

The polymeric powder build material can further comprise: (B) 0.1 to 1wt % antioxidants based on the total weight of the thermoplastic polymerpowder composition, (C) 0.1 to 5 wt % flow aids based on the totalweight of the thermoplastic polymer powder composition, (D) 0.2-5 wt %of a surface modifying agent based on the total weight of thethermoplastic polymer powder composition, (E) 0.05-wt %-5 wt %antistatic agents based on the total weight of the thermoplastic polymerpowder composition, (F) 10 wt % to 20 wt % filler based on the totalweight of the thermoplastic polymer powder composition, wherein thetotal of (a) to (f) is 100 wt %.

The polypropylene block copolymer can comprise the following particlesize distribution: D10: about 20 μm-about 45 μm; D50: about 50 μm-about85 μm; and D90: about 90 μm-about 140 μm.

The infrared absorbing compound can be a near infrared absorbingcompound.

The near infrared absorbing compound can be selected from the groupconsisting of carbon black, oxonol, squarylium,chalcogenopyrylarylidene, bis(chalcogenopyrylo)polymethine,bis(aminoaryl)polymethine, merocyanine, trinuclear cyanine,indene-crosslinked polymethine, oxyindolidine, iron complexes, quinoids,nickel-dithiolene complex, cyanine dyes, and combinations thereof.

The method described above can further comprise: selectively applying adetailing agent on the polymeric powder build material.

Disclosed herein is an example of a method of forming athree-dimensional printed part, the method comprising: depositing alayer of a polymeric powder build material comprising a thermoplasticpolymer powder composition, wherein the thermoplastic polymer powdercomposition comprises a polypropylene block copolymer made frompolymerizing propylene and ethylene or butylene and polypropylenehomopolymers; and exposing the build material composition to heat tofuse the at least a portion of the layer of the polymeric powder buildmaterial to form a layer of a 3D part.

Three-Dimensional Printed Parts

Disclosed herein is an example of a three-dimensional printed part madefrom three-dimensional printing, the three-dimensional part comprising:a thermoplastic polymer powder composition comprising a mixture of twoor more polyolefins including at least 60 wt % of a C3 polyolefin basedon the total weight of the mixture of the two or more polyolefins,wherein the thermoplastic polymer powder composition has a processingwindow of from about 120° C. to about 150° C.

The thermoplastic polymer powder composition can consist of apolypropylene block copolymer.

The three-dimensional printed part of can further comprise a filler.

The filler can be a filler is a reinforcing material selected from thegroup consisting of glass beads, fumed silica, hollow glass beads, glassfibers, crushed glass, silicon dioxide, aluminum oxide, calciumcarbonate, hydrous aluminum silicate, ceramic fibers, silicon carbidefibers, alumina fibers, carbon fibers, polypropylene fibers, polyamidefibers, polyoxymethylene fibers, ultra-high molecular weightpolyethylene fibers, polytetrafluoroethylene fibers, liquid crystalfibers, aramid (e.g., Kevlar®) fibers, and combinations thereof.

The filler can be a flame retarding compound selected from the groupconsisting of an alkali or earth alkali oxide, hydrate, sulfonate,sulphonamide salt, perfluoroborate, halogenated compound andphosphorus-bearing organic compound, and combinations thereof.

The filler can be an elastomeric material selected from the groupconsisting of styrene butadiene styrene block copolymers,styrene-ethylene/butylene-styrene block copolymer,styrene-isoprene-styrene block copolymer, hydrogenatedstyrene-isoprene-styrene block copolymer, ethylene-propylene rubber,ethylene propylene diene monomer rubber, and combinations thereof.

The polypropylene block copolymer can comprise the following particlesize distribution: D10: about 20 μm-about 45 μm; D50: about 50 μm-about85 μm; and D90: about 90 μm-about 140 μm.

The polypropylene block copolymer can have a melting peak temperature ofbetween about 130° C. and about 140° C. The polypropylene blockcopolymer can have a crystallization peak temperature of between about98° C. and about 105° C. The polypropylene block copolymer can have amelt flow index of at least about 4 g/10 min at about 190° C.

The three-dimensional printed part can have a tensile strength of atleast 15 MPa.

The three-dimensional printed part can further comprise: 0.05-wt %-5 wt% antistatic agents based on the total weight of the thermoplasticpolymer powder composition.

Disclosed herein is an example of a three-dimensional printed partcomprising: (a) at least 60 wt % of a polypropylene block copolymerbased on a total weight of the three-dimensional printed part, (b) 0.1to 1 wt % antioxidants based on the total weight of thethree-dimensional printed part, (c) 0.1 to 5 wt % flow aids based on thetotal weight of the three-dimensional printed part, (d) 0.05-wt %-5 wt %antistatic agents based on the total weight of the three-dimensionalprinted part, (e) 10 wt % to 20 wt % filler based on a total weight ofthe three-dimensional printed part.

The polypropylene block copolymer can comprise the following particlesize distribution: D10: about 20 μm-about 45 μm; D50: about 50 μm-about85 μm; and D90: about 90 μm-about 140 μm.

The filler can be a filler is a reinforcing material selected from thegroup consisting of glass beads, fumed silica, hollow glass beads, glassfibers, crushed glass, silicon dioxide, aluminum oxide, calciumcarbonate, hydrous aluminum silicate, ceramic fibers, silicon carbidefibers, alumina fibers, carbon fibers, polypropylene fibers, polyamidefibers, polyoxymethylene fibers, ultra-high molecular weightpolyethylene fibers, polytetrafluoroethylene fibers, liquid crystalfibers, aramid (e.g., Kevlar®) fibers, and combinations thereof.

The three-dimensional printed part can have a tensile strength of atleast 20 MPa.

The thermoplastic polymer powder composition can have a processingwindow of from about 120° C. to about 150° C.

Build Material

In some examples, a polymeric powder build material (also referred toherein as build material composition 16) can comprise a thermoplasticpolymer powder composition.

The thermoplastic polymer powder composition can include a C3 olefinpolymer (homopolymer, copolymer) such as a propylene homopolymer, apropylene copolymer, a propylene terpolymer, or combinations thereof.The comonomers can be ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene,4-methy-1-pentene, butadiene, and blends thereof. Examples of thethermoplastic polymer include ethylene-propylene random copolymer,ethylene-propylene alternate copolymer ethylene-propylene blockcopolymer, ethylene-propylene-butene terpolymer,ethylene-propylene-pentene terpolymer, ethylene-propylene-octeneterpolymer, ethylene-propylene-4-methyl-1-pentene terpolymer, physicalblends of these polymers produced by compounding and/or dry blending.

Among them, particularly suitable for use is a multi-stage polymerizedpropylene-based copolymer which is a polymer containing propylene-basedmonomer units, called “high-impact polypropylene” or “polypropyleneblock copolymer” containing a crystalline propylene-based polymerizedportion and amorphous propylene-based polymerized portion. Themulti-stage polymerized propylene-based copolymer is obtained bypolymerizing in multiple stages, a crystalline homopolypropylene portionor random copolymer portion in which a small amount of olefin other thanpropylene are copolymerized, and an amorphous rubber portion in whichethylene and propylene, and an olefin as an optional component otherthan ethylene and propylene are copolymerized, continuously in arbitraryorder in the presence of their respective polymers, whose limitingviscosity measured in 1, 2, 3, 4-tetrahydronaphthalene at 135° C.preferably falls within a range of 0.1 to 100 dl/g. This multi-stagepolymerized propylene-based copolymer has excellent heat resistance,rigidity and shock resistance, it can be used for automobile parts suchas bumper and door trim, a variety of packaging containers such asretort pouch food packaging containers.

Using the olefin polymerization reactor and the process for producingpolyolefin of the present invention, olefin polymer components havingdifferent molecular weights may be produced in respective polymerizationsteps to widen a molecular weight distribution of the olefin polymer. Insome examples, an olefin random copolymer or olefin block copolymer withan average molecular weight in number (Mn) between about 55,000 g/moland about 65,000 g/mol, average molecular weight in mass (Mw) betweenabout 280,000 g/mol and about 325,000 g/mol, and a polydispersity(PDI=Mw/Mn) of about 5 can be used.

In some examples, the olefin polymer can have a wider molecular weightdistribution, as long as it produces an olefin copolymer whose limitingzero-shear melt viscosity at about 190° C./0.001 Hz measured inplate-plate geometry is comprised between about 3000 and about 7000 Pa·sor as long as it produces a solution viscosity obtained in the abovemeasurement of a polymer component produced, for example, in apolymerization step of producing a polymer component having the largestmolecular weight falls within a range of preferably 0.5 to 100 dl/g,more preferably 1 to 50 dl/g and particularly preferably 2 to 20 dl/g,the limiting viscosity being equal to or more than 5 times limitingviscosity of a polymer component produced in the polymerization step ofproducing a polymer component having the smallest molecular weight, andthe amount of the polymer component produced in the polymerization stepof producing the polymer component having the largest molecular weightbeing contained in the olefin polymer to account for 0.1 to 80 weight %.

The polymerization catalyst can be any known addition polymerizationcatalyst used for olefin polymerization. Some examples of thepolymerization catalyst include a Ziegler-based solid catalyst obtainedby subjecting a solid catalyst component containing titanium, magnesium,a halogen and electron donor, an organic aluminum compound component,and an electron donor component in contact with each other; and ametallocene-based solid catalyst obtained by supporting a metallocenecompound and a co-catalyst component on a particulate carrier. Thesecatalysts may be used in combination.

In some examples, a chain-transfer agent such as hydrogen may also beused in combination to adjust the molecular weight of the polymer.

The above-described olefin polymerization catalyst may be a so-calledpreliminary polymerization catalyst polymerized beforehand with a smallamount of olefin. Examples of the olefin used for preliminarypolymerization include the olefin used for the aforementionedpolymerization. In this case, one type of olefin may be used singly ortwo or more types of olefin may be used in combination.

Examples of the process for producing a preliminary polymerizationcatalyst include slurry polymerization, vapor phase polymerization.Among them, slurry polymerization is used preferably. In this case, theproduction may be economically more advantageous. Production may beperformed using any one of batch type, semi-batch type and continuoustype.

In some examples, a composition for a three-dimensional object cancomprise a polymeric powder build material (also referred to herein asbuild material composition 16) comprising (a) a thermoplastic polymerpowder composition, wherein the thermoplastic polymer powder compositioncomprises a polypropylene block copolymer made from polymerizingpropylene and ethylene and/or polypropylene homopolymers with othercomonomers comprising 1-butene, 1-pentene, 1-hexene, 1-octene,4-methy-1-pentene, a fusing agent comprising at least one infraredabsorbing compound; and a detailing agent comprising at least at least60 wt % water based on the total weight of the detailing agent.

The polymeric powder build material can further comprise: (b) 0.1 to 1wt % antioxidants based on the total weight of the thermoplastic polymerpowder composition, (c) 0.1 to 5 wt % flow aids based on the totalweight of the thermoplastic polymer powder composition, (d) 0.2-5 wt %of a surface modifying agent based on the total weight of thethermoplastic polymer powder composition, (e) 0.05-wt %-5 wt %antistatic agents based on the total weight of the thermoplastic polymerpowder composition, (f) 10 wt % to 20 wt % filler based on the totalweight of the thermoplastic polymer powder composition, wherein thetotal of (a) to (f) is 100 wt %.

The polypropylene block copolymer can comprise the following particlesize distribution: D10: about 20 μm-about 45 μm; D50: about 50 μm-about85 μm; and D90: about 90 μm-about 140 μm. In some examples, D10 can beabout 15 μm-about 50 μm, or about 20 μm-about 45 μm, or about 25μm-about 40 μm, or about 30 μm-about 35 μm. In some examples, D50 can beabout 50 μm-about 85 μm, or about 55 μm-about 80 μm, or about 60μm-about 75 μm, or about 60 μm-about 70 μm, or about 50 μm-about 65 μm.In some examples, D90 can be about 85 μm-about 130 μm, or about 90μm-about 125 μm, or about 95 μm-about 115 μm, or about 110 μm-about 115μm.

The polypropylene block copolymer can have a melting peak temperature ofbetween about 130° C. and about 140° C., or between about 110° C. andabout 150° C., or between about 120° C. and about 130° C., or betweenabout 131° C. and about 139° C., or between about 132° C. and about 138°C., or between about 133° C. and about 137° C., or between about 134° C.and about 136° C., or about 135° C.

The polypropylene block copolymer can have a crystallization peaktemperature of between about 98° C. and about 105° C., or between about90° C. and about 110° C., or between about 91° C. and about 109° C., orbetween about 92° C. and about 108° C., or between about 93° C. andabout 107° C., or between about 94° C. and about 106° C., or betweenabout 95° C. and about 105° C., or between about 96° C. and about 104°C., or between about 97° C. and about 103° C., or between about 98° C.and about 102° C., between about 99° C. and about 101° C., or about 100°C.

The polypropylene block copolymer can have a melt flow index of at leastabout 4 g/10 min at about 190° C., or at least about 5 g/10 min at about190° C., or at least about 6 g/10 min at about 190° C., or at leastabout 7 g/10 min at about 190° C., or at least about 8 g/10 min at about190° C., or at least about 9 g/10 min at about 190° C., or at leastabout 10 g/10 min at about 190° C., or from about 3 g/10 min or to about11 g/10 min at about 190° C., or from about 4 g/10 min or to about 10g/10 min at about 190° C., or from about 5 g/10 min or to about 9 g/10min at about 190° C., or from about 6 g/10 min or to about 8 g/10 min atabout 190° C., or about 7 g/10 min at about 190° C.

The polypropylene block copolymer can have a zero-shear melt viscosityat 190° C. (measured in plate-plate geometry at 0.001 Hz) between about300 Pa·s and about 8000 Pa·s and more preferably between about 3000 Pa·sand about 7000 Pa·s

The polymeric powder build material may be made up of similarly sizedparticles or differently sized particles. The term “size” or “particlesize,” as used herein, refers to the diameter of a substantiallyspherical particle, or the average diameter of a non-spherical particle(i.e., the average of multiple diameters across the particle), or theeffective diameter of a non-spherical particle (i.e., the diameter of asphere with the same mass and density as the non-spherical particle). Asubstantially spherical particle (i.e., spherical or near-spherical) hasa sphericity of >0.84. Thus, any individual particles having asphericity of <0.84 are considered non-spherical (irregularly shaped).

In some examples, the thermoplastic polymer powder composition caninclude a polypropylene copolymer with an average molecular weight innumber (Mn) of between about 55,000 g/mol and about 65,000 g/mol, anaverage molecular weight in mass (Mw) between about 280,000 g/mol andabout 325,000 g/mol, and a polydispersity (PDI=Mw/Mn) of about 5. Insome examples, the PDI can be less than about 7, or less than about 6,or less than about 5, or less than about 4.

In some examples, the thermoplastic polymer powder composition caninclude a polypropylene copolymer with a zero-shear melt viscosity atabout 190° C. (measured in plate-plate geometry at 0.001 Hz) betweenabout 300 Pa·s and about 8000 Pa·s

Filler

In some examples, the build material can include one or more fillers.The fillers can be selected from natural or synthetic inorganic fillerssuch as glass beads, fumed silica, hollow glass beads, glass fibers,crushed glass, silicon dioxide, aluminum oxide, calcium carbonate,kaolin (hydrous aluminum silicate), and combinations thereof. Thefillers can be selected from ceramic fillers such ceramic fibers,silicon carbide fibers, alumina fiber, and combinations thereof. Thefillers can be selected from natural or synthetic organic fillers suchas synthetic fibers such as carbon fibers, polypropylene fibers,polyamide fibers, polyoxymethylene fibers, ultra-high molecular weightpolyethylene fibers, polytetrafluoroethylene fibers, liquid crystal(LCP) fibers, aramid (e.g., Kevlar®) fibers, and combinations thereof.

In some examples, the filler can include inorganic oxides, carbides,borides and nitrides having a Knoop hardness of at least 1200. In someexamples, the filler are inorganic oxides, nitrides, borides andcarbides of zirconium, tantalum, titanium, tungsten, boron, aluminum andberyllium. In some examples, the filler is silicon carbide and aluminumoxide.

The filler can be a filler is a reinforcing material selected from thegroup consisting of glass beads, fumed silica, hollow glass beads, glassfibers, crushed glass, silicon dioxide, aluminum oxide, calciumcarbonate, hydrous aluminum silicate, ceramic fibers, silicon carbidefibers, alumina fibers, carbon fibers, polypropylene fibers, polyamidefibers, polyoxymethylene fibers, ultra-high molecular weightpolyethylene fibers, polytetrafluoroethylene fibers, liquid crystalfibers, aramid (e.g., Kevlar®) fibers, and combinations thereof.

The filler can be a flame retarding compound selected from the groupconsisting of an alkali or earth alkali sulfonate, sulphonamide salt,perfluoroborate, halogenated compound and phosphorus-bearing organiccompound, and combinations thereof.

The filler can be an elastomeric material selected from the groupconsisting of styrene butadiene styrene block copolymers,styrene-ethylene/butylene-styrene block copolymer,styrene-isoprene-styrene block copolymer, hydrogenatedstyrene-isoprene-styrene block copolymer, ethylene-propylene rubber,ethylene propylene diene monomer rubber, and combinations thereof.

The fillers can be added to the build material in an amount of up toabout 30 wt % based on the total amount of the build material, or lessthan about 25 wt %, or less than about 20 wt %, or less than about 15 wt%, or less than about 10 wt %, or less than about 5 wt %.

In some examples, the build material composition can include glass as afiller. In an example, the glass is selected from the group consistingof solid glass beads, hollow glass beads, porous glass beads, glassfibers, crushed glass, and a combination thereof. In another example,the glass is selected from the group consisting of soda lime glass(Na₂O/CaO/SiO₂), borosilicate glass, phosphate glass, fused quartz, anda combination thereof. In still another example, the glass is selectedfrom the group consisting of soda lime glass, borosilicate glass, and acombination thereof. In yet other examples, the glass may be any type ofnon-crystalline silicate glass.

In some examples, a surface of the glass is modified with a functionalgroup selected from the group consisting of an acrylate functionalsilane, a methacrylate functional silane, an epoxy functional silane, anester functional silane, an amino functional silane, and a combinationthereof. Examples of glass modified with such functional groups and/orsuch functional groups that may be used to modify the glass areavailable from Potters Industries, LLC (e.g., an epoxy functional silaneor an amino functional silane), Gelest Inc. (e.g., an acrylatefunctional silane or a methacrylate functional silane), Sigma-Aldrich(e.g., an ester functional silane), etc.

In a specific example, the glass is selected from the group consistingof soda lime glass, borosilicate glass, phosphate glass, fused quartz,and a combination thereof; or a surface of the glass is modified with afunctional group selected from the group consisting of an acrylatefunctional silane, a methacrylate functional silane, an epoxy functionalsilane, an ester functional silane, an amino functional silane, and acombination thereof; or a combination thereof.

In some examples, the glass can be dry blended with the polymer buildmaterial. In other examples, the glass can be encapsulated by thepolymer build material. When the glass is encapsulated by the polymerbuild material, the polymer build material may form a continuous coating(i.e., none of the glass is exposed) or a substantially continuouscoating (i.e., 5% or less of the glass is exposed) on the glass. Whetherthe glass is dry blended with the polymer build material or encapsulatedby the polymer build material may depend, in part, on i) thecharacteristics of the glass, and ii) the 3D printer with which thebuild material composition is to be used. As an example, when the glassincludes glass fibers and/or crushed glass, the glass may beencapsulated by the polymer build material. As another example, whensegregation of dry blended polymer build material and glass may occurand cause damage to the 3D printer in which the build materialcomposition is to be used, the glass may be encapsulated by the polymerbuild material.

The polymer build material, the glass, and/or the encapsulated buildmaterial (i.e., the glass encapsulated by the polymer build material)may be made up of similarly sized particles or differently sizedparticles. The term “particle size”, as used herein, refers to thediameter of a spherical particle, or the average diameter of anon-spherical particle (i.e., the average of multiple diameters acrossthe particle), or the volume-weighted mean diameter of a particledistribution. In an example, the average particle size of the buildmaterial composition ranges from about 5 μm to about 100 μm. In anotherexample, the average particle size of the build material compositionranges from about 10 μm to about 100 μm.

In some examples, the average particle size(s) of the build materialcomposition may depend on whether the glass is dry blended with thepolymer build material or encapsulated by the polymer build material.When the glass is dry blended with the polymer build material, theaverage particle size of the polymer build material may range from about20 μm to about 200 μm, and the average particle size of the glass mayrange from about 5 μm to about 150 μm. In an example, the D50 (i.e., themedian of the particle size distribution, where ½ the population isabove this value and ½ is below this value) of the polymer buildmaterial may be about 60 μm.

When the glass is encapsulated by the polymer build material, theaverage particle size of the glass (prior to being coated) may rangefrom about 5 μm to about 100 μm. In another example, the averageparticle size of the glass (prior to being coated) may range from about30 μm to about 50 μm. The average particle size of the encapsulatedbuild material (i.e., the glass coated with the polymer build material)may depend upon the size of the glass prior to coating and the thicknessof the polymer build material that is applied to the glass. In anexample, the average particle size of the encapsulated build materialmay range from about 10 μm to about 200 μm. In another example, theaverage particle size of the encapsulated build material may range fromabout 20 μm to about 120 μm. In still another example, the D50 of theencapsulated build material may be about 60 μm.

The weight ratio of the glass to the polymer build material ranges fromabout 5:95 to about 60:40. In some examples, the weight ratio of theglass to the polymer build material ranges from about 10:90 to about60:40; or from about 20:80 to about 60:40; or from about 40:60 to about60:40; or from about 5:95 to about 40:60; or from about 5:95 to about50:50. In another example, the weight ratio of the glass to the polymerbuild material is 40:60. In still another example, the weight ratio ofthe glass to the polymer build material is 50:50. In yet anotherexample, the weight ratio of the glass to the polymer build material is60:40. In some instances, additives (e.g., antioxidant(s),brightener(s), charging agent(s), flow aid(s), etc.) may be included inthe polymer build material. In these instances, the weight of thepolymer build material, for the purpose of determining the weight ratioof the glass to the polymer build material, may include the weight ofthe additives in addition to the weight of the polymer. In otherinstances, the weight of the polymer build material, for the purpose ofdetermining the weight ratio of the glass to the polymer build material,includes the weight of the polymer alone (whether or not additives areincluded in the build material composition). The weight ratio of theglass to the polymer build material may depend, in part, on the desiredproperties of the 3D part to formed, the glass used, the polymer buildmaterial used, and/or the additives included in the polymer buildmaterial.

In some examples, the build material composition, in addition to thepolymer build material and the glass, may include an antioxidant, abrightener, a charging agent, a flow aid, or a combination thereof.While several examples of these additives are provided, it is to beunderstood that these additives are selected to be thermally stable(i.e., will not decompose) at the 3D printing process temperatures.

Antioxidants

Antioxidant(s) may be added to the build material composition to preventor slow molecular weight decreases of the polymer build material and/ormay prevent or slow discoloration (e.g., yellowing) of the polymer buildmaterial by preventing or slowing oxidation of the polymer buildmaterial. In some examples, the antioxidant may be a radical scavenger.In these examples, the antioxidant may include IRGANOX® 1098(benzenepropanamide,N,N′-1,6-hexanediylbis(3,5-bis(1,1-dimethylethyl)-4-hydroxy)), IRGANOX®254 (a mixture of 40% triethylene glycolbis(3-tert-butyl-4-hydroxy-5-methylphenyl), polyvinyl alcohol anddeionized water), and/or other sterically hindered phenols. In otherexamples, the antioxidant may include a phosphite and/or an organicsulfide (e.g., a thioester). In an example, the antioxidant may beincluded in the build material composition in an amount ranging fromabout 0.01 wt % to about 5 wt %, based on the total weight of the buildmaterial composition.

Flow Aids

Flow aid(s) may be added to improve the coating flowability of the buildmaterial composition. Flow aids may be particularly beneficial when thebuild material composition or the polymer build material has an averageparticle size less than 100 μm. The flow aid improves the flowability ofthe build material composition by reducing the friction, the lateraldrag, and the tribocharge buildup (by increasing the particleconductivity). Examples of suitable flow aids include tricalciumphosphate (E341), powdered cellulose (E460(ii)), calcium stearate(E470), magnesium stearate (E470b), sodium bicarbonate (E500), sodiumferrocyanide (E535), potassium ferrocyanide (E536), calcium ferrocyanide(E538), bone phosphate (E542), sodium silicate (E550), silicon dioxide(E551), calcium silicate (E552), magnesium trisilicate (E553a), talcumpowder (E553b), sodium aluminosilicate (E554), potassium aluminumsilicate (E555), calcium aluminosilicate (E556), bentonite (E558),aluminum silicate (E559), stearic acid (E570), and aluminum oxide. In anexample, the flow aid is added in an amount ranging from greater than 0wt % to less than 5 wt %, based upon the total weight of the buildmaterial composition.

Antistatic Agents

In some examples, antistatic agent(s) can be added to the buildmaterial. The antistatic agent(s) may include a salt of an alkali oralkaline earth metal. The salt of the alkali or alkaline earth metal mayinclude quaternary amines, chlorates, phosphates, carbonates, borates,phosphonates, sulfates, acetates, citrates, and perchlorates.Non-limiting examples of carbonates include sodium carbonates, potassiumcarbonates, lithium carbonates, barium carbonates, magnesium carbonates,calcium carbonates, ammonium carbonates, cobaltous carbonates, ferrouscarbonates, lead carbonates, manganese carbonates, and nickelcarbonates. Non-limiting examples of perchlorates include sodiumperchlorate, potassium perchlorate, lithium perchlorate, bariumperchlorate, magnesium perchlorate, calcium perchlorate, ammoniumperchlorate, cobaltous perchlorate, ferrous perchlorate, leadperchlorate, manganese perchlorate, and nickel perchlorate. Non-limitingexamples of chlorates include sodium chlorates, potassium chlorates,lithium chlorates, barium chlorates, magnesium chlorates, calciumchlorates, ammonium chlorates, cobaltous chlorates, ferrous chlorates,lead chlorates, manganese chlorates, and nickel chlorates. Non-limitingexamples of phosphates include sodium phosphates, potassium phosphates,lithium phosphates, barium phosphates, magnesium phosphates, calciumphosphates, ammonium phosphates, cobaltous phosphates, ferrousphosphates, lead phosphates, manganese phosphates, and nickelphosphates. The antistatic agent may also be a sulfonimide or asulfonamide, a neoalkoxy titanate and zirconate.

In some examples, the antistatic agent can be thermally stable at apolymer melt processing temperature.

In some examples, the antistatic agent can be selected from the groupconsisting of Li2NiBr4, Li2CuCl4, LiCuO, LiCu4O(PO4)2, LiSOCl2,LiSO2Cl2, LiSO2, LiI2, LiN3, C6H5COOLi, LiBr, Li2CO3, LiCl,C6H11(CH2)3CO2Li, LiBO2, LiClO4, Li3PO4, Li2SO4, Li2B4O7, LiAICl4,AuCl4Li, LiGaCl4, LiBF4, LiMnO2, LiFeS2, LiAg2CrO4, LiAg2V4O11, LiSVO,LiCSVO, CF3SO3Li, LiPF6, LiBF4, LiCIO4, LiCuS, LiPbCuS, LiFeS,LiBi2Pb2O5, LiBi2O3, LiV2O5, LiCoO2, LiNiCoO2, LiCuCl2, Li/Al—V2O5,lithium bis(oxalato)borate, LiN(SO2CF3)2, LiN(SOCF2CF3)2, LiAsF6,LiC(SO2CF3)3, LiN(SO2F)2, LiN(SO2F)(SO2CF3), LiN(SO2F)(SO2C4F9),LiOSO2CF3, and combinations thereof.

The antistatic agent may be present in the build material in an amountranging from about 0.01 wt. % to about 20 wt. % based upon the totalweight percent of the build material. In an example, the antistaticagent may be present in the build material in an amount ranging fromabout 0.1 wt. % to about 15 wt. %, for example, from about 2 wt. % toabout 13 wt. %, for example, about 4 wt. % based upon the total weightpercent of the composition.

Other Build Material Additives

Brightener(s) may be added to the build material composition to improvevisibility. Examples of suitable brighteners include titanium dioxide(TiO₂), zinc oxide (ZnO), calcium carbonate (CaCO₃), zirconium dioxide(ZrO₂), aluminum oxide (Al₂O₃), silicon dioxide (SiO₂), barium titanateand combinations thereof. In some examples, a stilbene derivative may beused as the brightener. In these examples, the temperature(s) of the 3Dprinting process may be selected so that the stilbene derivative remainsstable (i.e., the 3D printing temperature does not thermally decomposethe stilbene derivative). In an example, the brightener may be includedin the build material composition in an amount ranging from greater than0 wt % to about 10 wt %, based on the total weight of the build materialcomposition.

Charging agent(s) may be added to the build material composition tosuppress tribo-charging. Examples of suitable charging agents includealiphatic amines (which may be ethoxylated), aliphatic amides,quaternary ammonium salts (e.g., behentrimonium chloride orcocamidopropyl betaine), esters of phosphoric acid, polyethyleneglycolesters, or polyols. Some suitable commercially available chargingagents include HOSTASTAT® FA 38 (natural based ethoxylated alkylamine),HOSTASTAT® FE2 (fatty acid ester), and HOSTASTAT® HS 1 (alkanesulfonate), each of which is available from Clariant Int. Ltd.). In anexample, the charging agent is added in an amount ranging from greaterthan 0 wt % to less than 5 wt %, based upon the total weight of thebuild material composition.

The amounts of the above additives in the first fusing agent, the secondfusing agent, the color ink composition, and the detailing agent cantotal up to about 20 wt % based on the total weight of one of theagent(s)/composition(s).

Methods for Making Build Material Compositions

When a filler (e.g., glass) is blended with the polymer build material,the mixing is a dry blending process. The dry blending may beaccomplished by any suitable means. For example, the glass may be dryblended with the polymer build material using a mixer (e.g., anindustrial paddle mixer, an industrial high shear mixer, a resonantacoustic mixer, a ball mill, a powder mill, a jet mill, etc.). When themixer is used to dry blend the glass with the polymer build material,the mixer may be used at a setting that does not break the glass. Insome examples (e.g., when a jet mill is used), the mixer may be used forthe dry blending and may also be used to reduce the particle size of thepolymer build material. In these examples, the polymer build materialmay have a larger particle size at the beginning of the dry blendingprocess and may have a particle size within the desired range for thepolymer build material at the end of the dry blending process.

When the build material composition 16 includes the antioxidant, theflow aid, or a combination thereof, the method 100 may include mixingthe antioxidant, the brightener, the charging agent, the flow aid, or acombination thereof with the glass and polymer build material, before,after, or during the dry blending. Alternatively, the polymer buildmaterial may be obtained e.g., compounded with the antioxidant, thebrightener, the charging agent, and then dry mixed with the flow aid.

In the examples disclosed herein, it is to be understood that the dryblending may be performed in the printer 10 (see, e.g., FIG. 4 ), or ina separate powder management station. As examples, dry blending in theprinter 10 may take place in the build material supply 14 with suitablemixing hardware (not shown), or in a separate mixing station. In someexamples, the separate printing station may be set up to deliver the dryblended build material 16 to the supply and/or platform 12.

Kits for 3D Printing

As used herein, “material set” or “kit” is understood to be synonymouswith “composition.” Further, “material set” and “kit” are understood tobe compositions comprising one or more components where the differentcomponents in the compositions are each contained in one or morecontainers, separately or in any combination, prior to and duringprinting but these components can be combined together during printing.The containers can be any type of a vessel, box, or receptacle made ofany material.

Disclosed herein is an example of a three-dimensional printing kitcomprising: a polymeric powder build material comprising a thermoplasticpolymer powder composition, wherein the thermoplastic polymer powdercomposition comprises a polypropylene block copolymer made frompolymerizing propylene and ethylene or butylene and polypropylenehomopolymers; a fusing agent comprising at least one infrared absorbingcompound; and a detailing agent comprising at least 70 wt % water basedon the total weight of the detailing agent, wherein the polymeric powderbuild material, the fusing agent, and the detailing agent are eachhoused in separate containers. In some examples, the detailing agent cancomprise water in an amount of at least about 60 wt % based on the totalweight of the detailing agent. In some examples, the detailing agent cancomprise water in an amount of at least about 65 wt % based on the totalweight of the detailing agent. In some examples, the detailing agent cancomprise water in an amount of at least about 70 wt % based on the totalweight of the detailing agent. In some examples, the detailing agent cancomprise water in an amount of at least about 75 wt % based on the totalweight of the detailing agent. In some examples, the detailing agent cancomprise water in an amount of at least about 80 wt % based on the totalweight of the detailing agent. In some examples, the detailing agent cancomprise water in an amount of at least about 85 wt % based on the totalweight of the detailing agent. In some examples, the detailing agent cancomprise water in an amount of at least about 90 wt % based on the totalweight of the detailing agent.

Printing Methods

Referring now to FIG. 1 , disclosed is a method of forming a polymericpowder build material composition for three-dimensional printing 100,the method comprising: mixing 102 (A) a thermoplastic polymer powdercomposition comprising: at least 50 wt % of a C3 polyolefin, or amixture of two or more polyolefins including at least 60 wt % of a C3polyolefin based on the total weight of the mixture of the two or morepolyolefins, based on the total weight of the thermoplastic polymerpowder composition, (B) 0.1 to 1 wt % antioxidants based on the totalweight of the thermoplastic polymer powder composition, (C) 0.1 to 5 wt% flow aids based on the total weight of the thermoplastic polymerpowder composition, (D) 0-10 wt % of a surface modifying agent based onthe total weight of the thermoplastic polymer powder composition, (E)0.05-wt %-10 wt % antistatic agents based on the total weight of thethermoplastic polymer powder composition, (F) 2 wt % to 40 wt % fillerbased on the total weight of the thermoplastic polymer powdercomposition, wherein the total of (A) to (F) is 100 wt %, to form thepolymeric powder build material composition.

Referring now to FIG. 2 , disclosed is a method for three-dimensionalprinting 200 comprising: depositing a layer of a polymeric powder buildmaterial on a build platform 202, the polymeric powder build materialcomprising (A) a thermoplastic polymer powder composition, wherein thethermoplastic polymer powder composition comprises a polypropylene blockcopolymer made from polymerizing propylene and ethylene or butylene andpolypropylene homopolymers; based on a 3D object model, selectivelyapplying a fusing agent to at least a portion of the layer of thepolymeric powder build material 204, wherein the fusing agent comprisesat least one infrared absorbing compound; and exposing the buildmaterial composition to radiation to fuse the at least the portion toform a layer of a 3D part 206.

Referring now to FIG. 5 , disclosed is a method of forming athree-dimensional printed part, the method 500 comprising: depositing alayer of a polymeric powder build material comprising a thermoplasticpolymer powder composition 502, wherein the thermoplastic polymer powdercomposition comprises a polypropylene block copolymer made frompolymerizing propylene and ethylene or butylene and polypropylenehomopolymers; and exposing the build material composition to heat tofuse the at least a portion of the layer of the polymeric powder buildmaterial to form a layer of a 3D part 504.

Referring now to FIG. 2 and FIGS. 3A through 3E an example of a method200 for three-dimensional printing is depicted. Prior to execution ofthe method 200 or as part of the method 200, a controller 30 (see, e.g.,FIG. 4 ) may access data stored in a data store 32 (see, e.g., FIG. 4 )pertaining to a 3D part that is to be printed. The controller 30 maydetermine the number of layers of the build material composition 16 thatare to be formed and the locations at which the fusing agent 26 from theapplicator 24 is to be deposited on each of the respective layers.

Briefly, the method 200 for three-dimensional (3D) printing comprises:depositing a build material composition 16 to form a build materiallayer 38 (reference numeral 202); based on a 3D object model,selectively applying a fusing agent 26 on at least a portion 40 of thebuild material composition 16 (reference numeral 204); and exposing thebuild material composition 16 to radiation 44 to fuse the at least theportion 40 to form a layer 46 of a 3D part (reference numeral 206).

While not shown, the method 200 may include forming the build materialcomposition 16. In an example, the build material composition 16 isformed prior to applying the build material composition 16. The buildmaterial composition 16 may be formed in accordance with the method 100described above. To briefly reiterate from above, the build materialcomposition 16 may be formed by mixing the glass with the polymer buildmaterial. In other examples of the method 200 (e.g., when the glass isencapsulated by the polymer build material), the build materialcomposition 16 may be obtained (e.g., purchased) in the encapsulatedform.

As shown at reference numeral 202 in FIG. 2 and in FIGS. 3A and 3B, themethod 200 includes depositing the build material composition 16 to formthe build material layer 38.

It is noted that the build material composition 16 in FIGS. 3A through3E and FIG. 4 is shown as an encapsulated version of the build materialcomposition 16—i.e., filler encapsulating the polymer or polymerencapsulating the filler. However, it is to be understood that the buildmaterial composition 16 represents both an encapsulated version, anon-encapsulated version (i.e., polymer with no filler surrounding orsurrounded by filler), and a polymer with no filler version of the buildmaterial composition 16 may be used in the method 200.

In the example shown in FIGS. 3A and 3B, a printing system (e.g., theprinting system 10 shown in FIG. 4 ) may be used to apply the buildmaterial composition 16. The printing system 10 may include a build areaplatform 12, a build material supply 14 containing the build materialcomposition 16, and a build material distributor 18.

The build area platform 12 receives the build material composition 16from the build material supply 14. The build area platform 12 may bemoved in the directions as denoted by the arrow 20, e.g., along thez-axis, so that the build material composition 16 may be delivered tothe build area platform 12 or to a previously formed layer 46. In anexample, when the build material composition 16 is to be delivered, thebuild area platform 12 may be programmed to advance (e.g., downward)enough so that the build material distributor 18 can push the buildmaterial composition 16 onto the build area platform 12 to form asubstantially uniform layer 38 of the build material composition 16thereon. The build area platform 12 may also be returned to its originalposition, for example, when a new part is to be built.

The build material supply 14 may be a container, bed, or other surfacethat is to position the build material composition 16 between the buildmaterial distributor 18 and the build area platform 12.

The build material distributor 18 may be moved in the directions asdenoted by the arrow 22, e.g., along the y-axis, over the build materialsupply 14 and across the build area platform 12 to spread the layer 38of the build material composition 16 over the build area platform 12.The build material distributor 18 may also be returned to a positionadjacent to the build material supply 14 following the spreading of thebuild material composition 16. The build material distributor 18 may bea blade (e.g., a doctor blade), a roller, a combination of a roller anda blade, and/or any other device capable of spreading the build materialcomposition 16 over the build area platform 12. For instance, the buildmaterial distributor 18 may be a counter-rotating roller. In someexamples, the build material supply 14 or a portion of the buildmaterial supply 14 may translate along with the build materialdistributor 18 such that build material composition 16 is deliveredcontinuously to the material distributor 18 rather than being suppliedfrom a single location at the side of the printing system 10 as depictedin FIG. 3A.

As shown in FIG. 3A, the build material supply 14 may supply the buildmaterial composition 16 into a position so that it is ready to be spreadonto the build area platform 12. The build material distributor 18 mayspread the supplied build material composition 16 onto the build areaplatform 12. The controller 30 may process control build material supplydata, and in response, control the build material supply 14 toappropriately position the build material particles 16, and may processcontrol spreader data, and in response, control the build materialdistributor 18 to spread the supplied build material composition 16 overthe build area platform 12 to form the layer 38 of build materialcomposition 16 thereon. As shown in FIG. 3B, one build material layer 38has been formed.

The layer 38 of the build material composition 16 has a substantiallyuniform thickness across the build area platform 12. In an example, thethickness of the build material layer 38 is about 100 μm. In anotherexample, the thickness of the build material layer 38 ranges from about30 μm to about 300 μm, although thinner or thicker layers may also beused. For example, the thickness of the build material layer 38 mayrange from about 20 μm to about 500 μm, or from about 50 μm to about 80μm. The layer thickness may be about 2× (i.e., 2 times) the particlediameter (as shown in FIG. 3B) at a minimum for finer part definition.In some examples, the layer thickness may be about 1.2× the particlediameter.

After the build material composition 16 has been applied, and prior tofurther processing, the build material layer 38 may be exposed toheating. Heating may be performed to pre-heat the build materialcomposition 16, and thus the heating temperature may be below themelting point or softening point of the polymer of the build materialcomposition 16. As such, the temperature selected will depend upon thebuild material composition 16 that is used. As examples, the pre-heatingtemperature may be from about 5° C. to about 50° C. below the meltingpoint or softening point of the polymer of the build materialcomposition 16. In an example, the pre-heating temperature ranges fromabout 50° C. to about 250° C. In another example, the pre-heatingtemperature ranges from about 150° C. to about 170° C.

Pre-heating the layer 38 of the build material composition 16 may beaccomplished by using any suitable heat source that exposes all of thebuild material composition 16 on the build area platform 12 to the heat.Examples of the heat source include a thermal heat source (e.g., aheater (not shown) integrated into the build are platform 12 (which mayinclude sidewalls)) or the radiation source 34, 34′ (see, e.g., FIG. 4).

As shown at reference numeral 204 in FIG. 2 and in FIG. 3C, the method200 continues by, based on a 3D object model, selectively applying thefusing agent 26 on at least a portion 40 of the build materialcomposition 16. Example compositions of the fusing agent 26 aredescribed below.

It is to be understood that a single fusing agent 26 may be selectivelyapplied on the portion 40, or multiple fusing agents 26 may beselectively applied on the portion 40. As an example, multiple fusingagents 26 may be used to create a multi-colored part. As anotherexample, one fusing agent 26 may be applied to an interior portion of alayer and/or to interior layer(s) of a 3D part, and a fusing agent 26may be applied to the exterior portion(s) of the layer and/or to theexterior layer(s) of the 3D part. In the latter example, the color ofthe fusing agent 26 will be exhibited at the exterior of the part.

As illustrated in FIG. 3C, the fusing agent 26 may be dispensed from theapplicator 24. The applicator 24 may be a thermal inkjet printhead, apiezoelectric printhead, a continuous inkjet printhead, etc., and theselectively applying of the fusing agent 26 may be accomplished bythermal inkjet printing, piezo electric inkjet printing, continuousinkjet printing, etc.

The controller 30 may process data, and in response, control theapplicator 24 (e.g., in the directions indicated by the arrow 28) todeposit the fusing agent 26 onto predetermined portion(s) 40 of thebuild material layer 38 that are to become part of the 3D part. Theapplicator 24 may be programmed to receive commands from the controller30 and to deposit the fusing agent 26 according to a pattern of across-section for the layer of the 3D part that is to be formed. As usedherein, the cross-section of the layer of the 3D part to be formedrefers to the cross-section that is parallel to the surface of the buildarea platform 12. In the example shown in FIG. 3C, the applicator 24selectively applies the fusing agent 26 on those portion(s) 40 of thebuild material layer 38 that is/are to become the first layer of the 3Dpart. As an example, if the 3D part that is to be formed is to be shapedlike a cube or cylinder, the fusing agent 26 will be deposited in asquare pattern or a circular pattern (from a top view), respectively, onat least a portion of the build material layer 38. In the example shownin FIG. 3C, the fusing agent 26 is deposited on the portion 40 of thebuild material layer 38 and not on the portions 42.

The volume of the fusing agent 26 that is applied per unit of the buildmaterial composition 16 in the patterned portion 40 may be sufficient toabsorb and convert enough radiation 44 so that the build materialcomposition 16 in the patterned portion 40 will fuse/coalesce. Thevolume of the fusing agent 26 that is applied per unit of the buildmaterial composition 16 may depend, at least in part, on the radiationabsorber used, the radiation absorber loading in the fusing agent 26,and the build material composition 16 used.

As shown at reference numeral 206 in FIG. 2 and FIGS. 3C and 3D, themethod 200 continues by exposing the build material composition 16 toradiation 44 to fuse/coalesce the at least the portion 40 to form alayer 46 of a 3D part. The radiation 44 may be applied with the source34 of radiation 44 as shown in FIG. 3D or with the source 34′ ofradiation 44 as shown in FIG. 3C.

The fusing agent 26 enhances the absorption of the radiation 44,converts the absorbed radiation 44 to thermal energy, and promotes thetransfer of the thermal heat to the build material composition 16 incontact therewith. In an example, the fusing agent 26 sufficientlyelevates the temperature of the build material composition 16 in thelayer 38 above the melting or softening point of the polymer of thebuild material composition 16, allowing fusing/coalescing (e.g., thermalmerging, melting, binding, etc.) of the build material composition 16 totake place. The application of the radiation 44 forms the fused layer46, shown in FIG. 3D.

It is to be understood that portions 42 of the build material layer 38that do not have the fusing agent 26 applied thereto do not absorbenough radiation 44 to fuse/coalesce. As such, these portions 42 do notbecome part of the 3D part that is ultimately formed. The build materialcomposition 16 in portions 42 may be reclaimed to be reused as buildmaterial in the printing of another 3D part.

In some examples, the method 200 further comprises repeating theapplying of the build material composition 16, the selectively applyingof the fusing agent 26, and the exposing of the build materialcomposition 16, wherein the repeating forms the 3D part including thelayer 46. In these examples, the processes shown in FIG. 2 and FIGS. 3Athrough 3D may be repeated to iteratively build up several fused layersand to form the 3D printed part.

FIG. 3E illustrates the initial formation of a second build materiallayer on the previously formed layer 46. In FIG. 3E, following thefusing/coalescing of the predetermined portion(s) 40 of the buildmaterial composition 16, the controller 30 may process data, and inresponse cause the build area platform 12 to be moved a relatively smalldistance in the direction denoted by the arrow 20. In other words, thebuild area platform 12 may be lowered to enable the next build materiallayer to be formed. For example, the build material platform 12 may belowered a distance that is equivalent to the height of the buildmaterial layer 38. In addition, following the lowering of the build areaplatform 12, the controller 30 may control the build material supply 14to supply additional build material composition 16 (e.g., throughoperation of an elevator, an auger, or the like) and the build materialdistributor 18 to form another build material layer on top of thepreviously formed layer 46 with the additional build materialcomposition 16. The newly formed build material layer may be in someinstances pre-heated, patterned with the fusing agent 26, and thenexposed to radiation 44 from the source 34, 34′ of radiation 44 to formthe additional fused layer.

Several variations of the previously described method 200 will now bedescribed.

In some examples of the method 200, a detailing agent may be used. Thecomposition of the detailing agent is described below. The detailingagent may be dispensed from another (e.g., a second) applicator (whichmay be similar to applicator 24) and applied to portion(s) of the buildmaterial composition 16.

The detailing agent may provide an evaporative cooling effect to thebuild material composition 16 to which it is applied. The cooling effectof the detailing agent reduces the temperature of the build materialcomposition 16 containing the detailing agent during energy/radiationexposure. The detailing agent, and its rapid cooling effect, may be usedto obtain different levels of melting/fusing/binding within the layer 46of the 3D part that is being formed. Different levels ofmelting/fusing/binding may be desirable to control internal stressdistribution, warpage, mechanical strength performance, and/orelongation performance of the final 3D part.

In an example of using the detailing agent to obtain different levels ofmelting/fusing/binding within the layer 46, the fusing agent 26 may beselectively applied according to the pattern of the cross-section forthe layer 46 of the 3D part, and the detailing agent may be selectivelyapplied on at least some of that cross-section. As such, some examplesof the method 200 further comprise selectively applying, based on the 3Dobject model, the detailing agent on the at least some of the at leastthe portion 40 of the build material composition 16. The evaporativecooling provided by the detailing agent may remove energy from the atleast some of the portion 40; however, since the fusing agent 26 ispresent with the detailing agent, fusing is not completely prevented.The level of fusing may be altered due to the evaporative cooling, whichmay alter the internal stress distribution, warpage, mechanical strengthperformance, and/or elongation performance of the 3D part. It is to beunderstood that when the detailing agent is applied within the sameportion 40 as the fusing agent 26, the detailing agent may be applied inany desirable pattern. The detailing agent may be applied before, after,or at least substantially simultaneously (e.g., one immediately afterthe other in a single printing pass, or at the same time) with thefusing agent 26, and then the build material composition 16 is exposedto radiation.

In some examples, the detailing agent may also or alternatively beapplied after the layer 46 is fused to control thermal gradients withinthe layer 46 and/or the final 3D part. In these examples, the thermalgradients may be controlled with the evaporative cooling provided by thedetailing agent.

In another example that utilizes the evaporative cooling effect of thedetailing agent, the method 200 further comprises selectively applyingthe detailing agent on another portion 42 of the build materialcomposition 16 to aid in preventing the build material composition 16 inthe other portion 42 from fusing. In these examples, the detailing agentis selectively applied, based on the 3D object model, on the otherportion(s) 42 of the build material composition 16. The evaporativecooling provided by the detailing agent may remove energy from the otherportion 42, which may lower the temperature of the build materialcomposition 16 in the other portion 42 and prevent the build materialcomposition 16 in the other portion 42 from fusing/coalescing.

In some examples of the method 200 a coloring agent may be used. Thecoloring agent may be selected from the group consisting of a black ink,a cyan ink, a magenta ink, and a yellow ink. The composition of thecoloring agent is described below. The coloring agent may be dispensedfrom another (e.g., a third applicator which may be similar toapplicator 24) and applied to portion(s) of the build materialcomposition 16.

The coloring agent may color the build material composition 16 to whichit is applied. The color of the coloring agent may then be exhibited bythe 3D part. The coloring agent may be used to obtain colored ormulticolored 3D printed parts.

In an example, the fusing agent 26 may be selectively applied accordingto the pattern of the cross-section for the layer 46 of the 3D part, andthe coloring agent may be selectively applied on at least some of thatcross-section. As such, some examples of the method 200 further compriseselectively applying, based on the 3D object model, the coloring agenton the at least some of the at least the portion 40 of the buildmaterial composition 16, the coloring agent being selected from thegroup consisting of a black ink, a cyan ink, a magenta ink, and a yellowink. The coloring agent may cause the 3D part to exhibit the color(e.g., black, cyan, magenta, yellow, etc.) of the coloring agent.Multiple coloring agents may be used to impart multiple colors to the 3Dpart. It is to be understood that when the coloring agent(s) is/areapplied within the same portion 40 as the fusing agent 26, the coloringagent(s) may be applied in any desirable pattern. The coloring agent maybe applied before, after, or at least substantially simultaneously(e.g., one immediately after the other in a single printing pass, or atthe same time) with the fusing agent 26, and then the build materialcomposition 16 is exposed to radiation. In other examples, the coloringagent(s) may be applied to the finished 3D part. In these examples, thecoloring agent(s) may be used to add color(s) to the exterior of thepart.

In some examples, the method 200 further comprises: upon completion ofthe 3D part, placing the 3D part in an environment having a temperatureranging from about 15° C. to 30° C.; and maintaining the 3D part in theenvironment until a temperature of the 3D part reaches the temperatureof the environment. In these examples, the 3D part is allowed to cool ina room temperature environment (e.g., a temperature ranging from about15° C. to 30° C.) upon completion of the 3D part (e.g., within about 5minutes of forming the 3D part). As such, these examples of the method200 may be faster than examples that include heating the 3D part afterits formation (i.e., exposing the 3D part to an aging process).

In other examples, the method 200 further comprises heating the 3D partat a temperature ranging from greater than 30° C. to about 177° C. for atime period ranging from greater than 0 hours to about 144 hours. In anexample, the 3D part is heated at a temperature ranging from about 130°C. to about 177° C. In another example, the 3D part is heated at atemperature ranging from about 150° C. to about 177° C. In still anotherexample, the 3D part is heated a temperature ranging from about 165° C.to about 177° C. In yet another example, the 3D part is heated atemperature of about 165° C. In another example, the 3D part is heatedfor a time period ranging from greater than 0 hours to about 48 hours.In still another example, the 3D part is heated for about 22 hours. Thetime period for which the 3D part is heated may depend, in part, on thetemperature at which the 3D part is heated. For example, when thetemperature at which the 3D part is heated is higher (e.g., 165° C.) thetime period for which the 3D part is heated may be shorter (e.g., 22hours). As another example, when the temperature at which the 3D part isheated is lower (e.g., 35° C.) the time period for which the 3D part isheated may be longer (e.g., 140 hours).

Heating may be accomplished by any suitable means. For example, the 3Dpart may be heated in an oven. Heating the 3D part after its formationmay further increase the ultimate tensile strength of the 3D part (ascompared to ultimate tensile strength of a 3D part that was allowed tocool in a room temperature environment upon completion of the 3D part).

In an example of the method 200, the 3D part has an ultimate tensilestrength greater than or equal to 15 MPa. In another example, the 3Dpart formed by the method 200 has an ultimate tensile strength greaterthan or equal to 20 MPa. In any of these examples, the ultimate tensilestrength may be achieved whether the method 200 includes allowing the 3Dpart to cool after formation or the method 200 includes heating the 3Dpart after formation.

Printing Systems

Referring now to FIG. 4 , an example of a 3D printing system 10 isschematically depicted. It is to be understood that the 3D printingsystem 10 may include additional components (some of which are describedherein) and that some of the components described herein may be removedand/or modified.

Furthermore, components of the 3D printing system 10 depicted in FIG. 4may not be drawn to scale and thus, the 3D printing system 10 may have adifferent size and/or configuration other than as shown therein.

In an example, the three-dimensional (3D) printing system 10, comprises:a supply 14 of a build material composition; a build materialdistributor 18; a supply of a fusing agent 26; an applicator 24 forselectively dispensing the fusing agent 26; a source 34, 34′ ofradiation 44; a controller 30; and a non-transitory computer readablemedium having stored thereon computer executable instructions to causethe controller 30 to: utilize the build material distributor 18 todispense the build material composition 16; utilize the applicator 24 toselectively dispense the fusing agent 26 on at least a portion 40 of thebuild material composition 16; and utilize the source 34, 34′ ofradiation 44 to expose the build material composition 16 to radiation 44to fuse/coalesce the portion 40 of the build material composition 16.

In some examples, the 3D printing system 10 may further include a supplyof a detailing agent; a second applicator for selectively dispensing thedetailing agent; a supply of a coloring agent; and/or a third applicatorfor selectively dispensing the coloring agent (none of which are shown).In these examples, the computer executable instructions may furthercause the controller 30 to utilize the second applicator to selectivelydispense the detailing agent; and/or utilize the third applicator toselectively dispense the coloring agent on at least some of the at leastthe portion 40.

As shown in FIG. 4 , the printing system 10 includes the build areaplatform 12, the build material supply 14 containing the build materialcomposition 16 including the polymer build material and the glass, andthe build material distributor 18.

As mentioned above, the build area platform 12 receives the buildmaterial composition 16 from the build material supply 14. The buildarea platform 12 may be integrated with the printing system 10 or may bea component that is separately insertable into the printing system 10.For example, the build area platform 12 may be a module that isavailable separately from the printing system 10. The build materialplatform 12 that is shown is one example, and could be replaced withanother support member, such as a platen, a fabrication/print bed, aglass plate, or another build surface.

As also mentioned above, the build material supply 14 may be acontainer, bed, or other surface that is to position the build materialcomposition 16 between the build material distributor 18 and the buildarea platform 12. In some examples, the build material supply 14 mayinclude a surface upon which the build material composition 16 may besupplied, for instance, from a build material source (not shown) locatedabove the build material supply 14. Examples of the build materialsource may include a hopper, an auger conveyer, or the like.Additionally, or alternatively, the build material supply 14 may includea mechanism (e.g., a delivery piston) to provide, e.g., move, the buildmaterial composition 16 from a storage location to a position to bespread onto the build area platform 12 or onto a previously formed layer46 of the 3D part.

As also mentioned above, the build material distributor 18 may be ablade (e.g., a doctor blade), a roller, a combination of a roller and ablade, and/or any other device capable of spreading the build materialcomposition 16 over the build area platform 12 (e.g., a counter-rotatingroller).

As shown in FIG. 4 , the printing system 10 also includes the applicator24, which may contain the fusing agent 26. The applicator 24 may bescanned across the build area platform 12 in the directions indicated bythe arrow 28, e.g., along the y-axis. The applicator 24 may be, forinstance, a thermal inkjet printhead, a piezoelectric printhead, acontinuous inkjet printhead, etc., and may extend a width of the buildarea platform 12. While the applicator 24 is shown in FIG. 4 as a singleapplicator, it is to be understood that the applicator 24 may includemultiple applicators that span the width of the build area platform 12.Additionally, the applicators 24 may be positioned in multipleprintbars. The applicator 24 may also be scanned along the x-axis, forinstance, in configurations in which the applicator 24 does not span thewidth of the build area platform 12 to enable the applicator 24 todeposit the fusing agent 26 over a large area of the build materialcomposition 16. The applicator 24 may thus be attached to a moving XYstage or a translational carriage (neither of which is shown) that movesthe applicator 24 adjacent to the build area platform 12 in order todeposit the fusing agent 26 in predetermined areas 40 of the buildmaterial layer 38 that has been formed on the build area platform 12 inaccordance with the method 200 disclosed herein. The applicator 24 mayinclude a plurality of nozzles (not shown) through which the fusingagent 26 is to be ejected.

The applicator 24 may deliver drops of the fusing agent 26 at aresolution ranging from about 300 dots per inch (DPI) to about 1200 DPI.In other examples, the applicator 24 may deliver drops of the fusingagent 26 at a higher or lower resolution. The drop velocity may rangefrom about 5 m/s to about 24 m/s and the firing frequency may range fromabout 1 kHz to about 100 kHz. In one example, the volume of each dropmay be on the order of about 3 picoliters (pl) to about 18 pl, althoughit is contemplated that a higher or lower drop volume may be used. Insome examples, the applicator 24 is able to deliver variable dropvolumes of the fusing agent 26. One example of a suitable printhead has600 DPI resolution and can deliver drop volumes ranging from about 6 plto about 14 pl.

Each of the previously described physical elements may be operativelyconnected to a controller 30 of the printing system 10. The controller30 may process print data that is based on a 3D object model of the 3Dobject/part to be generated. In response to data processing, thecontroller 30 may control the operations of the build area platform 12,the build material supply 14, the build material distributor 18, and theapplicator 24. As an example, the controller 30 may control actuators(not shown) to control various operations of the 3D printing system 10components. The controller 30 may be a computing device, asemiconductor-based microprocessor, a central processing unit (CPU), anapplication specific integrated circuit (ASIC), and/or another hardwaredevice. Although not shown, the controller 30 may be connected to the 3Dprinting system 10 components via communication lines.

The controller 30 manipulates and transforms data, which may berepresented as physical (electronic) quantities within the printer'sregisters and memories, in order to control the physical elements tocreate the 3D part. As such, the controller 30 is depicted as being incommunication with a data store 32. The data store 32 may include datapertaining to a 3D part to be printed by the 3D printing system 10. Thedata for the selective delivery of the build material composition 16,the fusing agent 26, etc. may be derived from a model of the 3D part tobe formed. For instance, the data may include the locations on eachbuild material layer 38 that the applicator 24 is to deposit the fusingagent 26. In one example, the controller 30 may use the data to controlthe applicator 24 to selectively apply the fusing agent 26. The datastore 32 may also include machine readable instructions (stored on anon-transitory computer readable medium) that are to cause thecontroller 30 to control the amount of build material composition 16that is supplied by the build material supply 14, the movement of thebuild area platform 12, the movement of the build material distributor18, the movement of the applicator 24, etc.

As shown in FIG. 4 , the printing system 10 may also include a source34, 34′ of radiation 44. In some examples, the source 34 of radiation 44may be in a fixed position with respect to the build material platform12. The source 34 in the fixed position may be a conductive heater or aradiative heater that is part of the printing system 10. These types ofheaters may be placed below the build area platform 12 (e.g., conductiveheating from below the platform 12) or may be placed above the buildarea platform 12 (e.g., radiative heating of the build material layersurface). In other examples, the source 34′ of radiation 44 may bepositioned to apply radiation 44 to the build material composition 16immediately after the fusing agent 26 has been applied thereto. In theexample shown in FIG. 4 , the source 34′ of radiation 44 is attached tothe side of the applicator 24 which allows for patterning andheating/exposing to radiation 44 in a single pass.

The source 34, 34′ of radiation 44 may emit radiation 44 havingwavelengths ranging from about 100 nm to about 1 mm. As one example, theradiation 44 may range from about 800 nm to about 2 μm. As anotherexample, the radiation 44 may be blackbody radiation with a maximumintensity at a wavelength of about 1100 nm. The source 34, 34′ ofradiation 44 may be infrared (IR) or near-infrared light sources, suchas IR or near-IR curing lamps, IR or near-IR light emitting diodes(LED), or lasers with the desirable IR or near-IR electromagneticwavelengths.

The source 34, 34′ of radiation 44 may be operatively connected to alamp/laser driver, an input/output temperature controller, andtemperature sensors, which are collectively shown as radiation systemcomponents 36. The radiation system components 36 may operate togetherto control the source 34, 34′ of radiation 44. The temperature recipe(e.g., radiation exposure rate) may be submitted to the input/outputtemperature controller. During heating, the temperature sensors maysense the temperature of the build material composition 16, and thetemperature measurements may be transmitted to the input/outputtemperature controller. For example, a thermometer associated with theheated area can provide temperature feedback. The input/outputtemperature controller may adjust the source 34, 34′ of radiation 44power set points based on any difference between the recipe and thereal-time measurements. These power set points are sent to thelamp/laser drivers, which transmit appropriate lamp/laser voltages tothe source 34, 34′ of radiation 44. This is one example of the radiationsystem components 36, and it is to be understood that other radiationsource control systems may be used. For example, the controller 30 maybe configured to control the source 34, 34′ of radiation 44.

Fusing Agents

In the examples of the method 200 and the system 10 disclosed herein,and as mentioned above, a fusing agent 26 may be used. Examples of thefusing agent 26 are dispersions including a radiation absorber (i.e., anactive material). The active material may be any infrared lightabsorbing colorant.

In some examples, the fusing agent comprises a near infrared absorbingcompound.

In some examples, the near infrared absorbing compound is selected fromthe group consisting of carbon black, oxonol, squarylium,chalcogenopyrylarylidene, bis(chalcogenopyrylo)polymethine,bis(aminoaryl)polymethine, merocyanine, trinuclear cyanine,indene-crosslinked polymethine, oxyindolidine, iron complexes, quinoids,nickel-dithiolene complex, cyanine dyes, and combinations thereof.

The cyanine dyes can be selected from the group consisting ofcarbocyanine, azacarbocyanine, hem icyanine, styryl, diazacarbocyanine,triazacarbocyanine, diazahemicyanine, polymethinecyanine,azapolymethinecyanine, holopolar, indocyanine, diazahemicyanine dyes,and combinations thereof.

In some examples, the near infrared absorbing compound is carbon black.

In some examples, the fusing agent further comprises: at least oneco-solvent; at least one surfactant; at least one anti-kogation agent;at least one chelating agent; at least one buffer solution; at least onebiocide; and water.

In some examples, the fusing agent is added in the three-dimensionalprinting composition in an amount of from about 1 wt % to about 30 wt %based on the total weight of the three-dimensional printing composition,or from about 5 wt % to about 25 wt %, or from about 8 wt % to about 20wt %, or less than about 35 wt %, or less than about 25 wt %, or lessthan about 20 wt %, or less than about 15 wt %, or less than about 10 wt%, or at least about 1 wt %, or at least about 3 wt %, or at least about5 wt %, or at least about 8 wt %, or at least about 10 wt %, or at leastabout 15 wt %, or at least about 20 wt %, or at least about 30 wt %, orat least about 35 wt %.

In some examples, the near infrared absorbing compound in the fusingagent is present in an amount of at least about 1 wt % based on thetotal weight of fusing agent, or at least about 3 wt %, or at leastabout 5 wt %, or at least about 7 wt %, or at least about 10 wt %, or atleast 15 wt %, or less than about 20 wt %, or less than about 15 wt %,or less than about 12 wt %, or less than about 10 wt %, or less thanabout 8 wt %, or less than about 7 wt %, or less than about 6 wt %, orless than about 5 wt %.

The fusing agent 218 is a jettable composition. The fusing agentcomposition is an aqueous jettable composition that includes radiationabsorbing agent (i.e., an active material) and an aqueous vehicle.Examples of the fusing agent 218 are water-based dispersions including aradiation absorbing agent (i.e., an active material). The amount of theactive material in the fusing agent may depend upon how absorbing theactive material is. In an example, the fusing agent may include theactive material and may be applied in an amount sufficient to include atleast 0.01 wt % of the active material in the 3D part layer that isformed with the fusing agent. Even this low amount can produce a blackcolored part layer. The fusing agents tend to have significantabsorption (e.g., 80%) in the visible region (400 nm-780 nm). Thisabsorption generates heat suitable for fusing during 3D printing, whichleads to 3D parts having mechanical integrity and relatively uniformmechanical properties (e.g., strength, elongation at break, etc.). Theradiation absorbing agent is a dispersion of material in the aqueousvehicle. As used herein, the term “dispersion” refers to a two-phasessystem where one phase consists of finely divided radiation absorbingagent distributed throughout a bulk substance, i.e. liquid vehicle. Theradiation absorbing agent is the dispersed or internal phase and thebulk substance is the continuous or external phase (liquid vehicle). Asdisclosed herein the liquid medium is an aqueous liquid medium, i.e.comprising water.

The active material, or radiation absorbing agent, may be any infraredlight absorbing colorant that is black. In an example, the activematerial, or radiation absorbing agent is a near infrared absorbingcompound. Any near infrared black colorants may be used. In someexamples, the fusing agent includes near infrared absorbing compound andan aqueous vehicle.

In some examples, the active material, or radiation absorbing agent, isa carbon back pigment or near infrared absorbing dyes. In some otherexamples, the active material, or radiation absorbing agent, is a carbonback pigment; and the fusing agent composition may be an ink formulationincluding carbon black as the active material. Examples of this inkformulation are commercially known as CM997A, 5206458, C18928, C93848,C93808, or the like, all of which are available from HP Inc. In yet someother examples, the fusing agent may be an ink formulation includingnear infrared absorbing dyes as the active material.

The fusing agent composition is an aqueous formulation (i.e., includes abalance of water) that may also include any of the previously listedco-solvents, non-ionic surfactants, biocides, and/or anti-kogationagents. The fusing agent composition includes an aqueous vehicle asdefined above. In an example of the fusing agent composition, theco-solvents are present in an amount ranging from about 1 wt % to about60 wt % of the total wt % of the fusing agent composition, the non-ionicsurfactants are present in an amount ranging from about 0.5 wt. % toabout 1.5 wt. % based on the total wt. % of the fusing agentcomposition, the biocides are present in an amount ranging from about0.1 wt. % to about 5 wt. % based on the total wt. % of the fusing agentcomposition, and/or the anti-kogation agents are present in an amountranging from about 0.1 wt. % to about 5 wt. % based on the total wt. %of the fusing agent composition. Some examples of the fusing agentcomposition may also include a pH adjuster, which is used to control thepH of the agent. From 0 wt % to about 2 wt % (of the total wt % of thefusing agent) of the pH adjuster, for example, can be used.

In an example, the active material is a near-infrared light absorber.Any near-infrared colorants, e.g., those produced by Fabricolor, EastmanKodak, BASF, or Yamamoto, may be used in the fusing agent 26. As oneexample, the fusing agent 26 may be a printing liquid formulationincluding carbon black as the active material. Examples of this printingliquid formulation are commercially known as CM997A, 516458, C18928,C93848, C93808, or the like, all of which are available from HP Inc.Other suitable active materials include near-infrared absorbing dyes orplasmonic resonance absorbers.

As another example, the fusing agent 26 may be a printing liquidformulation including near-infrared absorbing dyes as the activematerial. Examples of this printing liquid formulation are described inU.S. Pat. No. 9,133,344, incorporated herein by reference in itsentirety. Some examples of the near-infrared absorbing dye arewater-soluble near-infrared absorbing dyes selected from the groupconsisting of:

and mixtures thereof. In the above formulations, M can be a divalentmetal atom (e.g., copper, etc.) or can have OSO₃Na axial groups fillingany unfilled valencies if the metal is more than divalent (e.g., indium,etc.), R can be hydrogen or any C₁-C₈ alkyl group (including substitutedalkyl and unsubstituted alkyl), and Z can be a counterion such that theoverall charge of the near-infrared absorbing dye is neutral. Forexample, the counterion can be sodium, lithium, potassium, NH₄ ⁺, etc.

Some other examples of the near-infrared absorbing dye are hydrophobicnear-infrared absorbing dyes selected from the group consisting of:

and mixtures thereof. For the hydrophobic near-infrared absorbing dyes,M can be a divalent metal atom (e.g., copper, etc.) or can include ametal that has Cl, Br, or OR′ (R′═H, CH₃, COCH₃, COCH₂COOCH₃,COCH₂COCH₃) axial groups filling any unfilled valencies if the metal ismore than divalent, and R can be hydrogen or any C₁-C₈ alkyl group(including substituted alkyl and unsubstituted alkyl).

Other near-infrared absorbing dyes or pigments may be used. Someexamples include anthroquinone dyes or pigments, metal dithiolene dyesor pigments, cyanine dyes or pigments, perylenediimide dyes or pigments,croconium dyes or pigments, pyrilium or thiopyrilium dyes or pigments,boron-dipyrromethene dyes or pigments, or aza-boron-dipyrromethene dyesor pigments.

Anthroquinone dyes or pigments and metal (e.g., nickel) dithiolene dyesor pigments may have the following structures, respectively:

where R in the anthroquinone dyes or pigments may be hydrogen or anyC₁-C₈ alkyl group (including substituted alkyl and unsubstituted alkyl),and R in the dithiolene may be hydrogen, COOH, SO₃, NH₂, any C₁-C₈ alkylgroup (including substituted alkyl and unsubstituted alkyl), or thelike.

Cyanine dyes or pigments and perylenediimide dyes or pigments may havethe following structures, respectively:

where R in the perylenediimide dyes or pigments may be hydrogen or anyC₁-C₈ alkyl group (including substituted alkyl and unsubstituted alkyl).

Croconium dyes or pigments and pyrilium or thiopyrilium dyes or pigmentsmay have the following structures, respectively:

Boron-dipyrromethene dyes or pigments and aza-boron-dipyrromethene dyesor pigments may have the following structures, respectively:

In other examples, the active material may be a plasmonic resonanceabsorber. The plasmonic resonance absorber allows the fusing agent 26 toabsorb radiation at wavelengths ranging from 800 nm to 4000 nm (e.g., atleast 80% of radiation having wavelengths ranging from 800 nm to 4000 nmis absorbed), which enables the fusing agent 26 to convert enoughradiation to thermal energy so that the build material composition 16fuses/coalesces. The plasmonic resonance absorber also allows the fusingagent 26 to have transparency at wavelengths ranging from 400 nm to 780nm (e.g., 20% or less of radiation having wavelengths ranging from 400nm to 780 nm is absorbed), which enables the 3D part to be white orslightly colored.

The absorption of the plasmonic resonance absorber is the result of theplasmonic resonance effects. Electrons associated with the atoms of theplasmonic resonance absorber may be collectively excited by radiation,which results in collective oscillation of the electrons. Thewavelengths that can excite and oscillate these electrons collectivelyare dependent on the number of electrons present in the plasmonicresonance absorber particles, which in turn is dependent on the size ofthe plasmonic resonance absorber particles. The amount of energy thatcan collectively oscillate the particle's electrons is low enough thatvery small particles (e.g., 1-100 nm) may absorb radiation withwavelengths several times (e.g., from 8 to 800 or more times) the sizeof the particles. The use of these particles allows the fusing agent 26to be inkjet jettable as well as electromagnetically selective (e.g.,having absorption at wavelengths ranging from 800 nm to 4000 nm andtransparency at wavelengths ranging from 400 nm to 780 nm).

In an example, the plasmonic resonance absorber has an average particlediameter (e.g., volume-weighted mean diameter) ranging from greater than0 nm to less than 220 nm. In another example the plasmonic resonanceabsorber has an average particle diameter ranging from greater than 0 nmto 120 nm. In a still another example, the plasmonic resonance absorberhas an average particle diameter ranging from about 10 nm to about 200nm.

In an example, the plasmonic resonance absorber is an inorganic pigment.Examples of suitable inorganic pigments include lanthanum hexaboride(LaB₆), tungsten bronzes (A_(x)WO₃), indium tin oxide (In₂O₃:SnO₂, ITO),antimony tin oxide (Sb₂O₃:SnO₂, ATO), titanium nitride (TiN), aluminumzinc oxide (AZO), ruthenium oxide (RuO₂), silver (Ag), gold (Au),platinum (Pt), iron pyroxenes (A_(x)Fe_(y)Si₂O₆ wherein A is Ca or Mg,x=1.5-1.9, and y=0.1-0.5), modified iron phosphates (A_(x)Fe_(y)PO₄),modified copper phosphates (A_(x)Cu_(y)PO_(z)), and modified copperpyrophosphates (A_(x)Cu_(y)P₂O₇). Tungsten bronzes may be alkali dopedtungsten oxides. Examples of suitable alkali dopants (i.e., A inA_(x)WO₃) may be cesium, sodium, potassium, or rubidium. In an example,the alkali doped tungsten oxide may be doped in an amount ranging fromgreater than 0 mol % to about 0.33 mol % based on the total mol % of thealkali doped tungsten oxide. Suitable modified iron phosphates(A_(x)Fe_(y)PO₇) may include copper iron phosphate (A=Cu, x=0.1-0.5, andy=0.5-0.9), magnesium iron phosphate (A=Mg, x=0.1-0.5, and y=0.5-0.9),and zinc iron phosphate (A=Zn, x=0.1-0.5, and y=0.5-0.9). For themodified iron phosphates, it is to be understood that the number ofphosphates may change based on the charge balance with the cations.Suitable modified copper pyrophosphates (A_(x)Cu_(y)P₂O₇) include ironcopper pyrophosphate (A=Fe, x=0-2, and y=0-2), magnesium copperpyrophosphate (A=Mg, x=0-2, and y=0-2), and zinc copper pyrophosphate(A=Zn, x=0-2, and y=0-2). Combinations of the inorganic pigments mayalso be used.

The amount of the active material that is present in the fusing agent 26ranges from greater than 0 wt % to about 40 wt % based on the totalweight of the fusing agent 26. In other examples, the amount of theactive material in the fusing agent 26 ranges from about 0.3 wt % to 30wt %, from about 1 wt % to about 20 wt %, from about 1.0 wt % up toabout 10.0 wt %, or from greater than 4.0 wt % up to about 15.0 wt %. Itis believed that these active material loadings provide a balancebetween the fusing agent 26 having jetting reliability and heat and/orradiation absorbance efficiency.

As used herein, “FA vehicle” may refer to the liquid in which the activematerial is dispersed or dissolved to form the fusing agent 26. A widevariety of FA vehicles, including aqueous and non-aqueous vehicles, maybe used in the fusing agent 26. In some examples, the FA vehicle mayinclude water alone or a non-aqueous solvent alone with no othercomponents. In other examples, the FA vehicle may include othercomponents, depending, in part, upon the applicator 24 that is to beused to dispense the fusing agent 26. Examples of other suitable fusingagent components include dispersant(s), silane coupling agent(s),co-solvent(s), surfactant(s), antimicrobial agent(s), anti-kogationagent(s), and/or chelating agent(s).

When the active material is the plasmonic resonance absorber, theplasmonic resonance absorber may, in some instances, be dispersed with adispersant. As such, the dispersant helps to uniformly distribute theplasmonic resonance absorber throughout the fusing agent 26. Examples ofsuitable dispersants include polymer or small molecule dispersants,charged groups attached to the plasmonic resonance absorber surface, orother suitable dispersants. Some specific examples of suitabledispersants include a water-soluble acrylic acid polymer (e.g.,CARBOSPERSE® K7028 available from Lubrizol), water-solublestyrene-acrylic acid copolymers/resins (e.g., JONCRYL® 296, JONCRYL®671, JONCRYL® 678, JONCRYL® 680, JONCRYL® 683, JONCRYL® 690, etc.available from BASF Corp.), a high molecular weight block copolymer withpigment affinic groups (e.g., DISPERBYK®-190 available BYK Additives andInstruments), or water-soluble styrene-maleic anhydridecopolymers/resins.

Whether a single dispersant is used or a combination of dispersants isused, the total amount of dispersant(s) in the fusing agent 26 may rangefrom about 10 wt % to about 200 wt % based on the weight of theplasmonic resonance absorber in the fusing agent 26.

When the active material is the plasmonic resonance absorber, a silanecoupling agent may also be added to the fusing agent 26 to help bond theorganic and inorganic materials. Examples of suitable silane couplingagents include the SILQUEST® A series manufactured by Momentive.

Whether a single silane coupling agent is used or a combination ofsilane coupling agents is used, the total amount of silane couplingagent(s) in the fusing agent 26 may range from about 0.1 wt % to about50 wt % based on the weight of the plasmonic resonance absorber in thefusing agent 26. In an example, the total amount of silane couplingagent(s) in the fusing agent 26 ranges from about 1 wt % to about 30 wt% based on the weight of the plasmonic resonance absorber. In anotherexample, the total amount of silane coupling agent(s) in the fusingagent 26 ranges from about 2.5 wt % to about 25 wt % based on the weightof the plasmonic resonance absorber.

The solvent of the fusing agent 26 may be water or a non-aqueous solvent(e.g., ethanol, acetone, n-methyl pyrrolidone, aliphatic hydrocarbons,etc.). In some examples, the fusing agent 26 consists of the activematerial and the solvent (without other components). In these examples,the solvent makes up the balance of the fusing agent 26.

Classes of organic co-solvents that may be used in a water-based fusingagent 26 include aliphatic alcohols, aromatic alcohols, diols, glycolethers, polyglycol ethers, 2-pyrrolidones, caprolactams, formamides,acetamides, glycols, and long chain alcohols. Examples of theseco-solvents include primary aliphatic alcohols, secondary aliphaticalcohols, 1,2-alcohols, 1,3-alcohols, 1,5-alcohols, 1,6-hexanediol orother diols (e.g., 1,5-pentanediol, 2-methyl-1,3-propanediol, etc.),ethylene glycol alkyl ethers, propylene glycol alkyl ethers, higherhomologs (C₆-C₁₂) of polyethylene glycol alkyl ethers, triethyleneglycol, tetraethylene glycol, tripropylene glycol methyl ether, N-alkylcaprolactams, unsubstituted caprolactams, both substituted andunsubstituted formamides, both substituted and unsubstituted acetamides,and the like. Other examples of organic co-solvents include dimethylsulfoxide (DMSO), isopropyl alcohol, ethanol, pentanol, acetone, or thelike.

Other examples of suitable co-solvents include water-solublehigh-boiling point solvents, which have a boiling point of at least 120°C., or higher. Some examples of high-boiling point solvents include2-pyrrolidone (i.e., 2-pyrrolidinone, boiling point of about 245° C.),1-methyl-2-pyrrolidone (boiling point of about 203° C.),N-(2-hydroxyethyl)-2-pyrrolidone (boiling point of about 140° C.),2-methyl-1,3-propanediol (boiling point of about 212° C.), andcombinations thereof.

The co-solvent(s) may be present in the fusing agent 26 in a totalamount ranging from about 1 wt % to about 50 wt % based upon the totalweight of the fusing agent 26, depending upon the jetting architectureof the applicator 24. In an example, the total amount of theco-solvent(s) present in the fusing agent 26 is 25 wt % based on thetotal weight of the fusing agent 26.

The co-solvent(s) of the fusing agent 26 may depend, in part, upon thejetting technology that is to be used to dispense the fusing agent 26.For example, if thermal inkjet printheads are to be used, water and/orethanol and/or other longer chain alcohols (e.g., pentanol) may be thesolvent (i.e., makes up 35 wt % or more of the fusing agent 26) orco-solvents. For another example, if piezoelectric inkjet printheads areto be used, water may make up from about 25 wt % to about 30 wt % of thefusing agent 26, and the solvent (i.e., 35 wt % or more of the fusingagent 26) may be ethanol, isopropanol, acetone, etc. The co-solvent(s)of the fusing agent 26 may also depend, in part, upon the build materialcomposition 16 that is being used with the fusing agent 26.

The FA vehicle may also include humectant(s). In an example, the totalamount of the humectant(s) present in the fusing agent 26 ranges fromabout 3 wt % to about 10 wt %, based on the total weight of the fusingagent 26. An example of a suitable humectant is LIPONIC® EG-1 (i.e.,LEG-1, glycereth-26, ethoxylated glycerol, available from LipoChemicals).

In some examples, the FA vehicle includes surfactant(s) to improve thejettability of the fusing agent 26. Examples of suitable surfactantsinclude a self-emulsifiable, nonionic wetting agent based on acetylenicdiol chemistry (e.g., SURFYNOL® SEF from Evonik Resources EfficiencyGmbH), a nonionic fluorosurfactant (e.g., CAPSTONE® fluorosurfactants,such as CAPSTONE® FS-35, from DuPont, previously known as ZONYL FSO),and combinations thereof. In other examples, the surfactant is anethoxylated low-foam wetting agent (e.g., SURFYNOL® 440 or SURFYNOL®CT-111 from Evonik Resources Efficiency GmbH) or an ethoxylated wettingagent and molecular defoamer (e.g., SURFYNOL® 420 from Evonik ResourcesEfficiency GmbH). Still other suitable surfactants include non-ionicwetting agents and molecular defoamers (e.g., SURFYNOL® 104E from EvonikResources Efficiency GmbH) or water-soluble, non-ionic surfactants(e.g., TERGITOL™ TMN-6, TERGITOL™ 15-S-7, or TERGITOL™ 15-S-9 (asecondary alcohol ethoxylate) from The Dow Chemical Company or TEGO® Wet510 (polyether siloxane) available from Evonik). In some examples, itmay be desirable to utilize a surfactant having a hydrophilic-lipophilicbalance (HLB) less than 10.

Whether a single surfactant is used or a combination of surfactants isused, the total amount of surfactant(s) in the fusing agent 26 may rangefrom about 0.01 wt % to about 10 wt % based on the total weight of thefusing agent 26. In an example, the total amount of surfactant(s) in thefusing agent 26 may be about 3 wt % based on the total weight of thefusing agent 26.

An anti-kogation agent may be included in the fusing agent 26 that is tobe jetted using thermal inkjet printing. Kogation refers to the depositof dried printing liquid (e.g., fusing agent 26) on a heating element ofa thermal inkjet printhead. Anti-kogation agent(s) is/are included toassist in preventing the buildup of kogation. Examples of suitableanti-kogation agents include oleth-3-phosphate (e.g., commerciallyavailable as CRODAFOS™ O3A or CRODAFOS™ N-3 acid from Croda), or acombination of oleth-3-phosphate and a low molecular weight (e.g.,<5,000) polyacrylic acid polymer (e.g., commercially available asCARBOSPERSE™ K-7028 Polyacrylate from Lubrizol).

Whether a single anti-kogation agent is used or a combination ofanti-kogation agents is used, the total amount of anti-kogation agent(s)in the fusing agent 26 may range from greater than about 0.20 wt % toabout 0.65 wt % based on the total weight of the fusing agent 26. In anexample, the oleth-3-phosphate is included in an amount ranging fromabout 0.20 wt % to about 0.60 wt %, and the low molecular weightpolyacrylic acid polymer is included in an amount ranging from about0.005 wt % to about 0.03 wt %.

The FA vehicle may also include antimicrobial agent(s). Suitableantimicrobial agents include biocides and fungicides. Exampleantimicrobial agents may include the NUOSEPT™ (Troy Corp.), UCARCIDE™(Dow Chemical Co.), ACTICIDE® B20 (Thor Chemicals), ACTICIDE® M20 (ThorChemicals), ACTICIDE® MBL (blends of 2-methyl-4-isothiazolin-3-one(MIT), 1,2-benzisothiazolin-3-one (BIT) and Bronopol) (Thor Chemicals),AXIDE™ (Planet Chemical), NIPACIDE™ (Clariant), blends of5-chloro-2-methyl-4-isothiazolin-3-one (CIT or CMIT) and MIT under thetradename KATHON™ (Dow Chemical Co.), and combinations thereof. Examplesof suitable biocides include an aqueous solution of1,2-benzisothiazolin-3-one (e.g., PROXEL® GXL from Arch Chemicals,Inc.), quaternary ammonium compounds (e.g., BARDAC® 2250 and 2280,BARQUAT® 50-65B, and CARBOQUAT® 250-T, all from Lonza Ltd. Corp.), andan aqueous solution of methylisothiazolone (e.g., KORDEK® MLX from DowChemical Co.).

In an example, the fusing agent 26 may include a total amount ofantimicrobial agents that ranges from about 0.05 wt % to about 1 wt %.In an example, the antimicrobial agent(s) is/are a biocide(s) and is/arepresent in the fusing agent 26 in an amount of about 0.25 wt % (based onthe total weight of the fusing agent 26).

Chelating agents (or sequestering agents) may be included in the FAvehicle to eliminate the deleterious effects of heavy metal impurities.Examples of chelating agents include disodium ethylenediaminetetraaceticacid (EDTA-Na), ethylene diamine tetra acetic acid (EDTA), andmethylglycinediacetic acid (e.g., TRILON® M from BASF Corp.).

Whether a single chelating agent is used or a combination of chelatingagents is used, the total amount of chelating agent(s) in the fusingagent 26 may range from greater than 0 wt % to about 2 wt % based on thetotal weight of the fusing agent 26. In an example, the chelatingagent(s) is/are present in the fusing agent 26 in an amount of about0.04 wt % (based on the total weight of the fusing agent 26).

Detailing Agents

In the examples of the method 200 and the system 10 disclosed herein,and as mentioned above, a detailing agent may be used. The detailingagent may include a surfactant, a co-solvent, and a balance of water. Insome examples, the detailing agent consists of these components, and noother components. In some other examples, the detailing agent mayfurther include a colorant. In still some other examples, detailingagent consists of a colorant, a surfactant, a co-solvent, and a balanceof water, with no other components. In yet some other examples, thedetailing agent may further include additional components, such asanti-kogation agent(s), antimicrobial agent(s), and/or chelatingagent(s) (each of which is described above in reference to the fusingagent 26).

The surfactant(s) that may be used in the detailing agent include any ofthe surfactants listed above in reference to the fusing agent 26. Thetotal amount of surfactant(s) in the detailing agent may range fromabout 0.10 wt % to about 5.00 wt % with respect to the total weight ofthe detailing agent.

The co-solvent(s) that may be used in the detailing agent include any ofthe co-solvents listed above in reference to the fusing agent 26. Thetotal amount of co-solvent(s) in the detailing agent may range fromabout 1.00 wt % to about 20.00 wt % with respect to the total weight ofthe detailing agent.

Similar to the fusing agent 26, the co-solvent(s) of the detailing agentmay depend, in part upon the jetting technology that is to be used todispense the detailing agent. For example, if thermal inkjet printheadsare to be used, water and/or ethanol and/or other longer chain alcohols(e.g., pentanol) may make up 35 wt % or more of the detailing agent. Foranother example, if piezoelectric inkjet printheads are to be used,water may make up from about 25 wt % to about 30 wt % of the detailingagent, and 35 wt % or more of the detailing agent may be ethanol,isopropanol, acetone, etc.

In some examples, the detailing agent does not include a colorant. Inthese examples, the detailing agent may be colorless. As used herein,“colorless,” means that the detailing agent is achromatic and does notinclude a colorant.

When the detailing agent includes the colorant, the colorant may be adye of any color having substantially no absorbance in a range of 650 nmto 2500 nm. By “substantially no absorbance” it is meant that the dyeabsorbs no radiation having wavelengths in a range of 650 nm to 2500 nm,or that the dye absorbs less than 10% of radiation having wavelengths ina range of 650 nm to 2500 nm. The dye is also capable of absorbingradiation with wavelengths of 650 nm or less. As such, the dye absorbsat least some wavelengths within the visible spectrum, but absorbslittle or no wavelengths within the near-infrared spectrum. This is incontrast with the active material in the fusing agent 26, which absorbswavelengths within the near-infrared spectrum. As such, the colorant inthe detailing agent will not substantially absorb the fusing radiation,and thus will not initiate melting and fusing of the build materialcomposition 16 in contact therewith when the build material layer 38 isexposed to the fusing radiation.

The dye selected as the colorant in the detailing agent may also have ahigh diffusivity (i.e., it may penetrate into greater than 10 μm and upto 100 μm of the build material composition particles 16). The highdiffusivity enables the dye to penetrate into the build materialcomposition particles 16 upon which the detailing agent is applied, andalso enables the dye to spread into portions of the build materialcomposition 16 that are adjacent to the portions of the build materialcomposition 16 upon which the detailing agent is applied. The dyepenetrates deep into the build material composition 16 particles todye/color the composition particles. When the detailing agent is appliedat or just outside the edge boundary (of the final 3D part), the buildmaterial composition 16 particles at the edge boundary may be colored.In some examples, at least some of these dyed build material composition16 particles may be present at the edge(s) or surface(s) of the formed3D layer or part, which prevents or reduces any patterns (due to thedifferent colors of the fusing agent 26 and the build materialcomposition 16) from forming at the edge(s) or surface(s).

The dye in the detailing agent may be selected so that its color matchesthe color of the active material in the fusing agent 26. As examples,the dye may be any azo dye having sodium or potassium counter ion(s) orany diazo (i.e., double azo) dye having sodium or potassium counterion(s), where the color of azo or dye azo dye matches the color of thefusing agent 26.

In an example, the dye is a black dye. Some examples of the black dyeinclude azo dyes having sodium or potassium counter ion(s) and diazo(i.e., double azo) dyes having sodium or potassium counter ion(s).Examples of azo and diazo dyes may include tetrasodium(6Z)-4-acetamido-5-oxo-6-[[7-sulfonato-4-(4-sulfonatophenyl)azo-1-naphthyl]hydrazono]naphthalene-1,7-disulfonatewith a chemical structure of:

(commercially available as Food Black 1); tetrasodium6-amino-4-hydroxy-3-[[7-sulfonato-4-[(4-sulfonatophenyl)azo]-1-naphthyl]azo]naphthalene-2,7-disulfonatewith a chemical structure of:

(commercially available as Food Black 2); tetrasodium(6E)-4-amino-5-oxo-3-[[4-(2-sulfonatooxyethylsulfonyl)phenyl]diazenyl]-6-[[4-(2-sulfonatooxyethylsulfonyl)phenyl]hydrazinylidene]naphthalene-2,7-disulfonatewith a chemical structure of:

(commercially available as Reactive Black 31); tetrasodium(6E)-4-amino-5-oxo-3-[[4-(2-sulfonatooxyethylsulfonyl)phenyl]diazenyl]-6-[[4-(2-sulfonatooxyethylsulfonyl)phenyl]hydrazinylidene]naphthalene-2,7-disulfonatewith a chemical structure of:

and combinations thereof. Some other commercially available examples ofthe dye used in the detailing agent include multipurpose black azo-dyebased liquids, such as PRO-JET® Fast Black 1 (made available by FujifilmHoldings), and black azo-dye based liquids with enhanced water fastness,such as PRO-JET® Fast Black 2 (made available by Fujifilm Holdings).

In some instances, in addition to the black dye, the colorant in thedetailing agent may further include another dye. In an example, theother dye may be a cyan dye that is used in combination with any of thedyes disclosed herein. The other dye may also have substantially noabsorbance above 650 nm. The other dye may be any colored dye thatcontributes to improving the hue and color uniformity of the final 3Dpart.

Some examples of the other dye include a salt, such as a sodium salt, anammonium salt, or a potassium salt. Some specific examples includeethyl-[4-[[4-[ethyl-[(3-sulfophenyl) methyl] amino]phenyl]-(2-sulfophenyl)ethylidene]-1-cyclohexa-2,5-dienylidene]-[(3-sulfophenyl) methyl]azanium with a chemical structure of:

(commercially available as Acid Blue 9, where the counter ion mayalternatively be sodium counter ions or potassium counter ions); sodium4-[(E)-{4-[benzyl(ethyl)amino]phenyl}{(4E)-4-[benzyl(ethyl)iminio]cyclohexa-2,5-dien-1-ylidene}methyl]benzene-1,3-disulfonatewith a chemical structure of:

(commercially available as Acid Blue 7); and a phthalocyanine with achemical structure of:

(commercially available as Direct Blue 199); and combinations thereof.

In an example of the detailing agent, the dye may be present in anamount ranging from about 1.00 wt % to about 3.00 wt % based on thetotal weight of the detailing agent. In another example of the detailingagent including a combination of dyes, one dye (e.g., the black dye) ispresent in an amount ranging from about 1.50 wt % to about 1.75 wt %based on the total weight of the detailing agent, and the other dye(e.g., the cyan dye) is present in an amount ranging from about 0.25 wt% to about 0.50 wt % based on the total weight of the detailing agent.

The balance of the detailing agent is water. As such, the amount ofwater may vary depending upon the amounts of the other components thatare included.

Coloring Agents

In the examples of the method 100, 200, 500, and the system 10 disclosedherein, and as mentioned above, a coloring agent may be used. Thecoloring agent may include a colorant, a surfactant, a co-solvent, and abalance of water. In some examples, the coloring agent consists of thesecomponents, and no other components. In some other examples, thecoloring agent may further include additional components, such asdispersant(s), anti-kogation agent(s), antimicrobial agent(s), and/orchelating agent(s) (each of which is described above in reference to thefusing agent 26).

The coloring agent may be a black ink, a cyan ink, a magenta ink, or ayellow ink. As such, the colorant may be a black colorant, a cyancolorant, a magenta colorant, a yellow colorant, or a combination ofcolorants that together achieve a black, cyan, magenta, or yellow color.

In an example, the colorant may be present in the coloring agent in anamount ranging from about 0.1 wt % to about 10 wt % (based on the totalweight of the coloring agent). In another example, the colorant may bepresent in the coloring agent in an amount ranging from about 0.5 wt %to about 5 wt % (based on the total weight of the coloring agent). Instill another example, the colorant may be present in the coloring agentin an amount ranging from about 2 wt % to about 10 wt % (based on thetotal weight of the coloring agent).

In some examples, the colorant may be a dye. The dye may be non-ionic,cationic, anionic, or a combination thereof. Examples of dyes that maybe used include Sulforhodamine B, Acid Blue 113, Acid Blue 29, Acid Red4, Rose Bengal, Acid Yellow 17, Acid Yellow 29, Acid Yellow 42, AcridineYellow G, Acid Yellow 23, Acid Blue 9, Nitro Blue Tetrazolium ChlorideMonohydrate or Nitro BT, Rhodamine 6G, Rhodamine 123, Rhodamine B,Rhodamine B Isocyanate, Safranine O, Azure B, and Azure B Eosinate,which are available from Sigma-Aldrich Chemical Company (St. Louis,Mo.). Examples of anionic, water-soluble dyes include Direct Yellow 132,Direct Blue 199, Magenta 377 (available from Ilford AG, Switzerland),alone or together with Acid Red 52. Examples of water-insoluble dyesinclude azo, xanthene, methine, polymethine, and anthraquinone dyes.Specific examples of water-insoluble dyes include Orasol® Blue GN,Orasol® Pink, and Orasol® Yellow dyes available from Ciba-Geigy Corp.Black dyes may include Direct Black 154, Direct Black 168, Fast Black 2,Direct Black 171, Direct Black 19, Acid Black 1, Acid Black 191, MobayBlack SP, and Acid Black 2. The dye may also be any of the exampleslisted in reference to the detailing agent.

In other examples, the colorant may be a pigment. As used herein,“pigment” may generally include organic and/or inorganic pigmentcolorants that introduce color to the coloring agent and the 3D printedpart. The pigment can be self-dispersed with a polymer, oligomer, orsmall molecule or can be dispersed with a separate dispersant (describedabove in reference to the fusing agent 26).

Examples of pigments that may be used include Paliogen® Orange,Heliogen® Blue L 6901F, Heliogen® Blue NBD 7010, Heliogen® Blue K 7090,Heliogen® Blue L 7101F, Paliogen® Blue L 6470, Heliogen® Green K 8683,and Heliogen® Green L 9140 (available from BASF Corp.). Examples ofblack pigments include Monarch® 1400, Monarch® 1300, Monarch® 1100,Monarch® 1000, Monarch® 900, Monarch® 880, Monarch® 800, and Monarch®700 (available from Cabot Corp.). Other examples of pigments includeChromophtal® Yellow 3G, Chromophtal® Yellow GR, Chromophtal® Yellow 8G,Igrazin® Yellow SGT, Igralite® Rubine 4BL, Monastral® Magenta,Monastral® Scarlet, Monastral® Violet R, Monastral® Red B, andMonastral® Violet Maroon B (available from CIBA). Still other examplesof pigments include Printex® U, Printex® V, Printex® 140U, Printex®140V, Color Black FW 200, Color Black FW 2, Color Black FW 2V, ColorBlack FW 1, Color Black FW 18, Color Black S 160, Color Black S 170,Special Black 6, Special Black 5, Special Black 4A, and Special Black 4(available from Evonik). Yet other examples of pigments include Tipure®R-101 (available from DuPont), Dalamar® Yellow YT-858-D and HeucophthalBlue G XBT-583D (available from Heubach). Yet other examples of pigmentsinclude Permanent Yellow GR, Permanent Yellow G, Permanent Yellow DHG,Permanent Yellow NCG-71, Permanent Yellow GG, Hansa Yellow RA, HansaBrilliant Yellow 5GX-02, Hansa Yellow-X, Novoperm® Yellow HR, Novoperm®Yellow FGL, Hansa Brilliant Yellow 10GX, Permanent Yellow G3R-01,Hostaperm® Yellow H4G, Hostaperm® Yellow H3G, Hostaperm® Orange GR,Hostaperm® Scarlet GO, and Permanent Rubine F6B (available fromClariant). Yet other examples of pigments include Quindo® Magenta,Indofast® Brilliant Scarlet, Quindo® Red R6700, Quindo® Red R6713, andIndofast® Violet (available from Mobay). Yet other examples of pigmentsinclude L74-1357 Yellow, L75-1331 Yellow, and L75-2577 Yellow, LHD9303Black (available from Sun Chemical). Yet other examples of pigmentsinclude Raven® 7000, Raven® 5750, Raven® 5250, Raven® 5000, and Raven®3500 (available from Columbian).

When the coloring agent is applied at or just outside the edge boundary(of the final 3D part), the build material composition 16 at the edgeboundary may be colored. In some examples, at least some of these dyedbuild material composition 16 particles may be present at the edge(s) orsurface(s) of the formed 3D layer or part, which prevents or reduces anypatterns (due to the different colors of the fusing agent 26 and thebuild material composition 16) from forming at the edge(s) orsurface(s).

The surfactant(s) that may be used in the coloring agent include any ofthe surfactants listed above in reference to the fusing agent 26. Thetotal amount of surfactant(s) in the coloring agent may range from about0.01 wt % to about 20 wt % with respect to the total weight of thecoloring agent. In an example, the total amount of surfactant(s) in thecoloring agent may range from about 5 wt % to about 20 wt % with respectto the total weight of the coloring agent.

The co-solvent(s) that may be used in the coloring agent include any ofthe co-solvents listed above in reference to the fusing agent 26. Thetotal amount of co-solvent(s) in the coloring agent may range from about1 wt % to about 50 wt % with respect to the total weight of the coloringagent.

Similar to the fusing agent 26 and the detailing agent, theco-solvent(s) of the coloring agent may depend, in part upon the jettingtechnology that is to be used to dispense the coloring agent. Forexample, if thermal inkjet printheads are to be used, water and/orethanol and/or other longer chain alcohols (e.g., pentanol) may make up35 wt % or more of the coloring agent. For another example, ifpiezoelectric inkjet printheads are to be used, water may make up fromabout 25 wt % to about 30 wt % of the coloring agent, and 35 wt % ormore of the coloring agent may be ethanol, isopropanol, acetone, etc.

The balance of the coloring agent is water. As such, the amount of watermay vary depending upon the amounts of the other components that areincluded.

In some examples, the coloring agent can include a colorant, adispersant/dispersing additive, a co-solvent, and water. The coloringagent is a water-based inkjet composition. In some instances, thecoloring agent includes these components and no other components. Inother instances, the coloring agent may further include an anti-kogationagent, a biocide, a binder, and combinations thereof.

The colorant of the coloring agent is a pigment and/or dye having acolor other than white. Examples of the other colors include cyan,magenta, yellow, black, etc. In some instances, the colorant of thecolored ink may also be transparent to infrared wavelengths. Examples ofIR transparent colorants include acid yellow 23 (AY 23), AY17, acid red52 (AR 52), AR 289, and reactive red 180 (RR 180). In other instances,the colorant of the coloring agent may not be completely transparent toinfrared wavelengths, but does not absorb enough radiation tosufficiently heat the build material particles in contact therewith. Forexample, the colorant of the coloring agent may absorb some visiblewavelengths and some IR wavelengths. Some examples of these colorantsinclude cyan colorants, such as direct blue 199 (DB 199) and pigmentblue 15:3 (PB 15:3).

The coloring agent also includes the dispersing additive, which helps touniformly distribute the colorant throughout the coloring agent and aidin the wetting of the ink 230 onto the build material particles. Any ofthe dispersing additives discussed herein for the fusing agent may beused in the coloring agent. The dispersing additive may be present inthe coloring agent in a similar amount as the colorant.

In addition to the non-white colorant and the dispersing additives, thecoloring agent may include similar components as the fusing agent (e.g.,co-solvent(s), anti-kogation agent(s), biocide(s), water, etc.). Thecoloring agent may also include a binder, such as an acrylic latexbinder, which may be a copolymer of any two or more of styrene, acrylicacid, methacrylic acid, methyl methacrylate, ethyl methacrylate, andbutyl methacrylate. Some examples of the coloring agent may also includeother additives, such as a humectant and lubricant (e.g., Liponic® EG-1(LEG-1) from Lipo Chemicals), a chelating agent (e.g., disodium ethylenediamine-tetraacetic acid (EDTA-Na)), and/or a buffer.

An example of the pigment based coloring agent may include from about 1wt % to about 10 wt % of pigment(s), from about 10 wt % to about 30 wt %of co-solvent(s), from about 1 wt % to about 10 wt % of dispersingadditive(s), from 0.01 wt % to about 1 wt % of anti-kogation agent(s),from about 0.1 wt % to about 5 wt % of binder(s), from about 0.05 wt %to about 0.1 wt % biocide(s), and a balance of water. An example of thedye based coloring agent may include from about 1 wt % to about 7 wt %of dye(s), from about 10 wt % to about 30 wt % of co-solvent(s), fromabout 1 wt % to about 7 wt % of dispersing additive(s), from 0.05 wt %to about 0.1 wt % of chelating agent(s), from about 0.005 wt % to about0.2 wt % of buffer(s), from about 0.05 wt % to about 0.1 wt %biocide(s), and a balance of water.

In some examples, the coloring agent includes cyan ink composition (C),yellow ink composition (Y), magenta ink composition (M), and black inkcomposition (K). In some examples, additional ink compositions may beused in addition to the CYMK coloring agent.

The colorant(s) in the coloring agent(s) described herein can includeinorganic pigments, organic pigments, dyes, and combinations thereof.

The pigment may be any color, including, as examples, a cyan pigment, amagenta pigment, a yellow pigment, a black pigment, a violet pigment, agreen pigment, a brown pigment, an orange pigment, a purple pigment, awhite pigment, a metallic pigment (e.g., a gold pigment, a bronzepigment, a silver pigment, or a bronze pigment), a pearlescent pigment,or combinations thereof.

In some examples, the coloring agent includes cyan ink, yellow ink,magenta ink, and black ink.

Examples of suitable yellow organic pigments include C.I. Pigment Yellow1, C.I. Pigment Yellow 2, C.I. Pigment Yellow 3, C.I. Pigment Yellow 4,C.I. Pigment Yellow 5, C.I. Pigment Yellow 6, C.I. Pigment Yellow 7,C.I. Pigment Yellow 10, C.I. Pigment Yellow 11, C.I. Pigment Yellow 12,C.I. Pigment Yellow 13, C.I. Pigment Yellow 14, C.I. Pigment Yellow 16,C.I. Pigment Yellow 17, C.I. Pigment Yellow 24, C.I. Pigment Yellow 34,C.I. Pigment Yellow 35, C.I. Pigment Yellow 37, C.I. Pigment Yellow 53,C.I. Pigment Yellow 55, C.I. Pigment Yellow 65, C.I. Pigment Yellow 73,C.I. Pigment Yellow 74, C.I. Pigment Yellow 75, C.I. Pigment Yellow 77,C.I. Pigment Yellow 81, C.I. Pigment Yellow 83, C.I. Pigment Yellow 93,C.I. Pigment Yellow 94, C.I. Pigment Yellow 95, C.I. Pigment Yellow 97,C.I. Pigment Yellow 98, C.I. Pigment Yellow 99, C.I. Pigment Yellow 108,C.I. Pigment Yellow 109, C.I. Pigment Yellow 110, C.I. Pigment Yellow113, C.I. Pigment Yellow 114, C.I. Pigment Yellow 117, C.I. PigmentYellow 120, C.I. Pigment Yellow 122, C.I. Pigment Yellow 124, C.I.Pigment Yellow 128, C.I. Pigment Yellow 129, C.I. Pigment Yellow 133,C.I. Pigment Yellow 138, C.I. Pigment Yellow 139, C.I. Pigment Yellow147, C.I. Pigment Yellow 151, C.I. Pigment Yellow 153, C.I. PigmentYellow 154, C.I. Pigment Yellow 167, C.I. Pigment Yellow 172, C.I.Pigment Yellow 180, and C.I. Pigment Yellow 185.

Examples of suitable blue or cyan organic pigments include C.I. PigmentBlue 1, C.I. Pigment Blue 2, C.I. Pigment Blue 3, C.I. Pigment Blue 15,Pigment Blue 15:3, C.I. Pigment Blue 15:34, C.I. Pigment Blue 15:4, C.I.Pigment Blue 16, C.I. Pigment Blue 18, C.I. Pigment Blue 22, C.I.Pigment Blue 25, C.I. Pigment Blue 60, C.I. Pigment Blue 65, C.I.Pigment Blue 66, C.I. Vat Blue 4, and C.I. Vat Blue 60.

Examples of suitable magenta, red, or violet organic pigments includeC.I. Pigment Red 1, C.I. Pigment Red 2, C.I. Pigment Red 3, C.I. PigmentRed 4, C.I. Pigment Red 5, C.I. Pigment Red 6, C.I. Pigment Red 7, C.I.Pigment Red 8, C.I. Pigment Red 9, C.I. Pigment Red 10, C.I. Pigment Red11, C.I. Pigment Red 12, C.I. Pigment Red 14, C.I. Pigment Red 15, C.I.Pigment Red 16, C.I. Pigment Red 17, C.I. Pigment Red 18, C.I. PigmentRed 19, C.I. Pigment Red 21, C.I. Pigment Red 22, C.I. Pigment Red 23,C.I. Pigment Red 30, C.I. Pigment Red 31, C.I. Pigment Red 32, C.I.Pigment Red 37, C.I. Pigment Red 38, C.I. Pigment Red 40, C.I. PigmentRed 41, C.I. Pigment Red 42, C.I. Pigment Red 48(Ca), C.I. Pigment Red48(Mn), C.I. Pigment Red 57(Ca), C.I. Pigment Red 57:1, C.I. Pigment Red88, C.I. Pigment Red 112, C.I. Pigment Red 114, C.I. Pigment Red 122,C.I. Pigment Red 123, C.I. Pigment Red 144, C.I. Pigment Red 146, C.I.Pigment Red 149, C.I. Pigment Red 150, C.I. Pigment Red 166, C.I.Pigment Red 168, C.I. Pigment Red 170, C.I. Pigment Red 171, C.I.Pigment Red 175, C.I. Pigment Red 176, C.I. Pigment Red 177, C.I.Pigment Red 178, C.I. Pigment Red 179, C.I. Pigment Red 184, C.I.Pigment Red 185, C.I. Pigment Red 187, C.I. Pigment Red 202, C.I.Pigment Red 209, C.I. Pigment Red 219, C.I. Pigment Red 224, C.I.Pigment Red 245, C.I. Pigment Red 286, C.I. Pigment Violet 19, C.I.Pigment Violet 23, C.I. Pigment Violet 32, C.I. Pigment Violet 33, C.I.Pigment Violet 36, C.I. Pigment Violet 38, C.I. Pigment Violet 43, andC.I. Pigment Violet 50.

Examples of carbon black pigments include those manufactured byMitsubishi Chemical Corporation, Japan (such as, e.g., carbon black No.2300, No. 900, MCF88, No. 33, No. 40, No. 45, No. 52, MA7, MA8, MA100,and No. 2200B); various carbon black pigments of the RAVEN® seriesmanufactured by Columbian Chemicals Company, Marietta, Ga., (such as,e.g., RAVEN® 5750, RAVEN® 5250, RAVEN® 5000, RAVEN® 3500, RAVEN® 1255,and RAVEN® 700); various carbon black pigments of the BLACK PEARLS®series, REGAL® series, the MOGUL® series, or the MONARCH® seriesmanufactured by Cabot Corporation, Boston, Mass., (such as, e.g., BLACKPEARLS® 880 Carbon Black, REGAL® 400R, REGAL® 330R, and REGAL® 660R);and various black pigments manufactured by Evonik Degussa Corporation,Parsippany, N.J., (such as, e.g., Color Black FW1, Color Black FW2,Color Black FW2V, Color Black FW18, Color Black FW200, Color Black S150,Color Black S160, Color Black S170, PRINTEX® 35, PRINTEX® U, PRINTEX® V,PRINTEX® 140U, Special Black 5, Special Black 4A, and Special Black 4).An example of an organic black pigment includes aniline black, such asC.I. Pigment Black 1.

Some examples of green organic pigments include C.I. Pigment Green 1,C.I. Pigment Green 2, C.I. Pigment Green 4, C.I. Pigment Green 7, C.I.Pigment Green 8, C.I. Pigment Green 10, C.I. Pigment Green 36, and C.I.Pigment Green 45.

Examples of brown organic pigments include C.I. Pigment Brown 1, C.I.Pigment Brown 5, C.I. Pigment Brown 22, C.I. Pigment Brown 23, C.I.Pigment Brown 25, C.I. Pigment Brown 41, and C.I. Pigment Brown 42.

Some examples of orange organic pigments include C.I. Pigment Orange 1,C.I. Pigment Orange 2, C.I. Pigment Orange 5, C.I. Pigment Orange 7,C.I. Pigment Orange 13, C.I. Pigment Orange 15, C.I. Pigment Orange 16,C.I. Pigment Orange 17, C.I. Pigment Orange 19, C.I. Pigment Orange 24,C.I. Pigment Orange 34, C.I. Pigment Orange 36, C.I. Pigment Orange 38,C.I. Pigment Orange 40, C.I. Pigment Orange 43, and C.I. Pigment Orange66.

A suitable metallic pigment includes a metal chosen from gold, silver,platinum, nickel, chromium, tin, zinc, indium, titanium, copper,aluminum, and alloys of any of these metals. These metals may be usedalone or in combination with two or more metals or metal alloys. Someexamples of metallic pigments include STANDART® R0100, STANDART® R0200,and DORADO® gold-bronze pigments (available from Eckart Effect Pigments,Wesel, Germany).

In some examples, the above pigments can be used alone or in anycombination with one another.

The total amount of the colorant(s) in the coloring agent(s) ranges fromabout 0.1 wt % to about 15 wt % based on the total weight of thecoloring agent(s). In some examples, the total amount of the colorant(s)in the coloring agent(s) ranges from about 1 wt % to about 8 wt % basedon the total weight of the coloring agent(s).

In some examples, the average particle size of these colorant(s) mayrange from about 80 nm to about 400 nm.

In some examples, the above-described colorant(s) can be dispersed intoa polymeric dispersion. In some examples, the colorant(s) (e.g.,pigment(s)) can be dispersed in a dispersion comprising a styreneacrylic polymer. The polymeric dispersion comprising a styrene acrylicpolymer can assist in dispersing the pigment in a solvent system.

A variety of styrene acrylic polymers can be used for the pigmentdispersion. Some non-limiting commercial examples of useful styreneacrylic polymers are sold under the trade names JONCRYL® (S.C. JohnsonCo.), UCAR™ (Dow Chemical Co.), JONREZ® (MeadWestvaco Corp.), andVANCRYL® (Evonik Resources Efficiency GmbH).

In further detail, the styrene acrylic polymer can be formulated with avariety of monomers, such as hydrophilic monomers, hydrophobic monomers,or combinations thereof. Non-limiting examples of hydrophilic monomersthat can be co-polymerized together to form the styrene acrylic polymerinclude acrylic acid, methacrylic acid, ethacrylic acid, dimethylacrylicacid, maleic anhydride, maleic acid, vinylsulfonate, cyanoacrylic acid,vinylacetic acid, allylacetic acid, ethylidineacetic acid,propylidineacetic acid, crotonoic acid, fumaric acid, itaconic acid,sorbic acid, angelic acid, cinnamic acid, styrylacrylic acid, citraconicacid, glutaconic acid, aconitic acid, phenylacrylic acid,acryloxypropionic acid, aconitic acid, phenylacrylic acid,acryloxypropionic acid, vinylbenzoic acid, N-vinylsuccinamidic acid,mesaconic acid, methacroylalanine, acryloylhydroxyglycine, sulfoethylmethacrylic acid, sulfopropyl acrylic acid, styrene sulfonic acid,sulfoethylacrylic acid, 2-methacryloyloxymethane-1-sulfonic acid,3-methacryoyloxypropane-1-sulfonic acid, 3-(vinyloxy)propane-1-sulfonicacid, ethylenesulfonic acid, vinyl sulfuric acid, 4-vinylphenyl sulfuricacid, ethylene phosphonic acid, vinyl phosphoric acid, vinyl benzoicacid, 2-acrylamido-2-methyl-1-propanesulfonic acid, the like, orcombinations thereof.

Non-limiting examples of hydrophobic monomers that can be used includestyrene, p-methyl styrene, methyl methacrylate, hexyl acrylate, hexylmethacrylate, butyl acrylate, butyl methacrylate, ethyl acrylate, ethylmethacrylate, propyl acrylate, propyl methacrylate, octadecyl acrylate,octadecyl methacrylate, stearyl methacrylate, vinylbenzyl chloride,isobornyl acrylate, tetrahydrofurfuryl acrylate, 2-phenoxyethylmethacrylate, ethoxylated nonyl phenol methacrylate, isobornylmethacrylate, cyclohexyl methacrylate, t-butyl methacrylate, n-octylmethacrylate, lauryl methacrylate, trydecyl methacrylate, alkoxylatedtetrahydrofurfuryl acrylate, isodecyl acrylate, isobornylmethacrylate,the like, or combinations thereof.

The styrene acrylic polymer can have a weight average molecular weight(Mw) from about 3,000 g/mol to about 30,000 g/mol. In yet otherexamples, the styrene acrylic polymer can have an Mw from about 4,000g/mol to about 25,000 g/mol, or from about 4,500 g/mol to about 22,000g/mol.

In each instance where molecular weight is referred to, it is to beunderstood that this refers to weight average molecular weight in g/mol.

Further, in some examples, the styrene acrylic polymer can have an acidnumber or acid value from about 120 mg KOH/g to about 300 mg KOH/g. Inyet other examples, the styrene acrylic polymer can have an acid numberfrom about 140 mg KOH/g to about 260 mg KOH/g, from about 160 mg KOH/gto about 240 mg KOH/g, or from about 180 mg KOH/g to about 230 mg KOH/g.An acid number can be defined as the number of milligrams of potassiumhydroxide to neutralize 1 gram of the substance.

In some examples, the amount of styrene acrylic polymer in the coloringagent(s) can be from about 0.1 wt % to about 20 wt % based on the totalweight of the coloring agent(s), or from about 0.5 wt % to about 10 wt %based on the total weight of the coloring agent(s), or from about 1 wt %to about 5 wt % based on the total weight of the coloring agent(s).

In some examples, the amount of styrene acrylic polymer in the coloringagent(s) can be based on the amount of the colorant(s) in the coloringagent(s). Thus, in some examples, the colorant(s) and the styreneacrylic polymer can be present in the coloring agent(s) at a particularweight ratio. In some specific examples, the pigment and styrene acrylicpolymer can be present at a weight ratio of from 1:1 to 10:1. In otherexamples, the pigment and the styrene acrylic polymer can be present ata weight ratio of from about 2:1 to about 10:1. In yet other examples,the pigment and the styrene acrylic polymer can be present at a weightratio of from about 3:1 to about 6:1.

Surface Modifying Agents/Surfactants

Surface modifying agent(s) or surfactant(s) (used interchangeablyherein) may be used to improve the wetting properties and thejettability of the fusing agent and/or the detailing agent (alsoreferred to herein as agent). Examples of suitable surfactants mayinclude a self-emulsifiable, nonionic wetting agent based on acetylenicdiol chemistry, a nonionic fluorosurfactant, and combinations thereof.In other examples, the surfactant may be an ethoxylated low-foam wettingagent or an ethoxylated wetting agent and molecular defoamer. Stillother suitable surfactants include non-ionic wetting agents andmolecular defoamers or water-soluble, non-ionic surfactants. In someexamples, it may be desirable to utilize a surfactant having ahydrophilic-lipophilic balance (HLB) less than 10. Whether a singlesurfactant is used or a combination of surfactants is used, the totalamount of surfactant(s) in the agent may range from about 0.1 wt % toabout 3 wt % based on the total wt % of the agent.

In some examples, the other surfactants can include wetting agent(s)and/or surface tension reducing agent(s).

Examples of suitable wetting agents can include non-ionic surfactants.Some specific examples include a self-emulsifiable, non-ionic wettingagent based on acetylenic diol chemistry (e.g., SURFYNOL® SEF fromEvonik Resources Efficiency GmbH), a non-ionic fluorosurfactant (e.g.,CAPSTONE® fluorosurfactants from DuPont, previously referred as ZONYLFSO), and combinations thereof. In other examples, the wetting agent isan ethoxylated low-foam wetting agent (e.g., SURFYNOL® 440 or SURFYNOL®CT-111 from Evonik Resources Efficiency GmbH) or an ethoxylated wettingagent and molecular defoamer (e.g., SURFYNOL® 420 from Evonik ResourcesEfficiency GmbH). Still other suitable wetting agents include non-ionicwetting agents and molecular defoamers (e.g., SURFYNOL® 104E from EvonikResources Efficiency GmbH) or water-soluble, non-ionic surfactants(e.g., TERGITOL™ TMN-6, TERGITOL™ 15S7, and TERGITOL™ 15S9 from The DowChemical Company). In some examples, an anionic surfactant may be usedin combination with the non-ionic surfactant. In some examples, it maybe appropriate to utilize a wetting agent having ahydrophilic-lipophilic balance (HLB) less than 10.

In some examples, wetting agent(s) may be present in the fusing agent(s)and/or detailing agent(s) in an amount ranging from about 0.1 wt % toabout 4 wt % of the total weight of the compositions/agents. In anexample, the amount of the wetting agent(s) present in thecompositions/agents is about 0.1 wt % based on the total weight of thecompositions/agents. In another example, the amount of the wettingagent(s) present in the compositions/agents is about 0.04 wt % based onthe total weight of the compositions/agents.

The fusing agent(s) and/or detailing agent(s) may also include surfacetension reduction agent(s). Any of the previously mentioned wettingagents/surfactants may be used to reduce the surface tension. As anexample, the surface tension reduction agent may be theself-emulsifiable, non-ionic wetting agent based on acetylenic diolchemistry (e.g., SURFYNOL® SEF from Evonik Resources Efficiency GmbH).

The surface tension reduction agent(s) may be present in thecompositions/agents in an amount ranging from about 0.1 wt % to about 4wt % of the total weight of the compositions/agents. In an example, theamount of the surface tension reduction agent(s) present in thecompositions/agents is about 1.5 wt % based on the total weight of thecompositions/agents. In another example, the amount of the surfacetension reduction agent(s) present in the compositions/agents is about0.6 wt % compositions/agents.

When a surfactant is both a wetting agent and a surface tensionreduction agent, any of the ranges presented herein for the wettingagent and the surface tension reduction agent may be used for thesurfactant.

Other Additives in Fusing/Detailing Agents

In some examples, the fusing agent and/or the detailing agent (alsoreferred to herein as agent(s)/composition(s)) may further include abuffer solution, a surfactant, a dispersant, an anti-kogation agent, adispersing additive, a biocide, a chelating agent, at least onechelating agent, and combinations thereof.

In some examples, the agent(s)/composition(s) may further include buffersolution(s). In some examples, the buffer solution(s) can withstandsmall changes (e.g., less than 1) in pH when small quantities of awater-soluble acid or a water-soluble base are added to a compositioncontaining the buffer solution(s). The buffer solution(s) can have pHranges from about 5 to about 9.5, or from about 7 to about 9, or fromabout 7.5 to about 8.5.

In some examples, the buffer solution(s) can be added to theagent(s)/composition(s) in amounts ranging from about 0.01 wt % to about20 wt %, or from 0.1 wt % to about 15 wt %, or from about 0.1 wt % toabout 10 wt % based on the total weight of the agent(s)/composition(s).

In some examples, the buffer solution(s) can include at least onepoly-hydroxy functional amine.

In some examples, the buffer solution(s) can be 2-[4-(2-hydroxyethyl)piperazin-1-yl] ethane sulfonic acid,2-amino-2-(hydroxymethyl)-1,3-propanediol (TRIZMA® sold bySigma-Aldrich), 3-morpholinopropanesulfonic acid, triethanolamine,2-[bis-(2-hydroxyethyl)-amino]-2-hydroxymethyl propane-1,3-diol (bistris methane), N-methyl-D-glucamine,N,N,N′N′-tetrakis-(2-hydroxyethyl)-ethylenediamine andN,N,N′N′-tetrakis-(2-hydroxypropyl)-ethylenediamine, beta-alanine,betaine, or mixtures thereof.

In some examples, the buffer solution(s) can be2-amino-2-(hydroxymethyl)-1,3-propanediol (TRIZMA® sold bySigma-Aldrich), beta-alanine, betaine, or mixtures thereof.

The agent(s)/composition(s) in some examples can be dispersed with adispersing additive. The dispersing additive can help to uniformlydistribute colorant(s) throughout the agent(s)/composition(s). Thedispersing additive may also aid in the wetting of theagent(s)/composition(s) onto any other applied agent(s)/composition(s)and/or the layer(s) of the build material.

The dispersing additive may be present in the agent(s)/composition(s) inan amount ranging from about 0.01 wt % to about 2 wt % based on thetotal weight of the agent(s)/composition(s), or less than about 1.5 wt%, or less than about 1 wt %, or at least 0.01 wt %, or at least about0.1 wt %, or at least about 0.5 wt %.

Some examples of the dispersing additive can include a water solubleacrylic acid polymer (e.g., CARBOSPERSE® K7028 available from Lubrizol),a high molecular weight block copolymer with pigment affinic groups(e.g., DISPERBYK®-190 available BYK Additives and Instruments), andcombinations thereof.

The agent(s)/composition(s) can further include the dispersant toprovide particular wetting properties when applied to the layer(s) ofthe build material. The dispersant can help uniformly distribute theink(s) on the layer(s) of the build material.

The dispersant may be present in the agent(s)/composition(s) in anamount ranging from about 0.01 wt % to about 2 wt % based on the totalweight of the agent(s)/composition(s), or less than about 1.5 wt %, orless than about 1 wt %, or at least 0.01 wt %, or at least about 0.1 wt%, or at least about 0.5 wt %.

The dispersant may be non-ionic, cationic, anionic, or combinationsthereof. Some examples of the dispersant include a self-emulsifiable,non-ionic wetting agent based on acetylenic diol chemistry (e.g.,SURFYNOL® SEF from Evonik Resources Efficiency GmbH), an ethoxylatedlow-foam wetting agent (e.g., SURFYNOL® 440 and SURFYNOL® 465 fromEvonik Resources Efficiency GmbH), a non-ionic acetylenic diol surfaceactive agent (e.g., SURFYNOL® 104 from Evonik Resources EfficiencyGmbH), a non-ionic, alkylphenylethoxylate and solvent free surfactantblend (e.g., SURFYNOL® CT-211 from Evonik Resources Efficiency GmbH), anon-ionic organic surfactant (e.g., TEGO® Wet 510 from Evonik IndustriesAG), a non-ionic fluorosurfactant (e.g., CAPSTONE® fluorosurfactantsfrom DuPont, previously known as ZONYL FSO, POLYFOX™ PF-154N from OmnovaSolutions Inc.), non-ionic a secondary alcohol ethoxylate (e.g.,TERGITOL® 15-S-5, TERGITOL® 15-S-7, TERGITOL® 15-S-9, and TERGITOL®15-S-30 all from Dow Chemical Company), a water-soluble non-ionicsurfactant (e.g., TERGITOL® TMN-6), and combinations thereof. Examplesof anionic dispersants include those in the DOWFAX™ family (from DowChemical Company), and examples of cationic dispersants includedodecyltrimethylammonium chloride and hexadecyldimethylammoniumchloride. Combinations of any of the previously listed dispersants mayalso be used.

Examples of anti-kogation agents include oleth-3-phosphate orpolyoxyethyene (3) oleyl mono/di-phosphate (e.g., Crodafos® N-3A fromCroda, now Crodafos® O3A), aqueous dispersion of fumed alumina or fumedsilica (e.g., CAB—O-SPERSE® from Cabot Corp.), a metalchelator/chelating agent, such as methylglycinediacetic acid (e.g.,Trilon® M from BASF Corp.), and combinations thereof.

The anti-kogation agents may be present in the agent(s)/composition(s)in an amount ranging from about 0.01 wt % to about 2 wt % based on thetotal weight of the agent(s)/composition(s), or less than about 1.5 wt%, or less than about 1 wt %, or at least 0.01 wt %, or at least about0.1 wt %, or at least about 0.5 wt %.

Examples of biocides include 1,2-benzisothiazolin-3-one as the activeingredient in ACTICIDE® B-20 (available from Thor GmbH),2-methyl-4-isothiazolin-3-one as the active ingredient in ACTICIDE® M-20(available from Thor GmbH), an aqueous solution of1,2-benzisothiazolin-3-one (e.g., PROXEL® GXL from Arch Chemicals,Inc.), quaternary ammonium compounds (e.g., Bardac® 2250 and 2280,Barquat® 50-65B, and Carboquat® 250-T, all from Lonza Ltd. Corp.), anaqueous solution of methylisothiazolone (e.g., Kordek® MLX from The DowChemical Co.), and combinations thereof.

The biocides may be present in the agent(s)/composition(s) in an amountranging from about 0.01 wt % to about 2 wt % based on the total weightof the agent(s)/composition(s), or less than about 1.5 wt %, or lessthan about 1 wt %, or at least 0.01 wt %, or at least about 0.1 wt %, orat least about 0.5 wt %.

The agent(s)/composition(s) may also include a binder or otheradditives, such as a humectant and lubricant (e.g., LIPONIC® EG-1(LEG-1) from Lipo Chemicals) or a chelating agent (e.g., disodiumethylenediaminetetraacetic acid (EDTA-Na)).

The amounts of the above additives in the first fusing agent, the secondfusing agent, the color ink composition, and the detailing agent cantotal up to about 20 wt % based on the total weight of one of theagent(s)/composition(s).

Co-Solvent(s)

In some examples, each of the agent(s)/composition(s) described hereincan include at least one co-solvent. The co-solvent can be present in anamount ranging from about 0.1 wt % to about 50 wt % based on the totalweight of each of the agent(s)/composition(s), or less than about 60 wt%, or less than about 50 wt %, or less than about 45 wt %, or less thanabout 40 wt %, or less than about 35 wt %, or less than about 30 wt %,or less than about 25 wt %, or less than about 20 wt %, or less thanabout 15 wt %, or less than about 10 wt %, or less than about 5 wt %, orat least about 10 wt %, or at least about 15 wt %, or at least about 20wt %, or at least about 25 wt %, or at least about 30 wt %, or at leastabout 35 wt %, or at least about 40 wt %, or at least about 45 wt %, orat least about 50 wt %.

Some examples of co-solvents can include 2-pyrrolidinone,hydroxyethyl-2-pyrrolidone, diethylene glycol, 2-methyl-1,3-propanediol,tetraethylene glycol, tripropylene glycol methyl ether, dipropyleneglycol methyl ether, tripropylene glycol butyl ether, dipropylene glycolbutyl ether, triethylene glycol butyl ether, 1,2-hexanediol,2-hydroxyethyl pyrrolidinone, 2-hydroxyethyl-2-pyrrolidinone,1,6-hexanediol, and combinations thereof.

Water

The balance of the agent(s)/composition(s) is water. As such, the amountof water may vary depending upon the amounts of the nanoparticle(s),near infrared absorbing compound(s), and colorant(s).

In some examples, water can be present in the agent(s)/composition(s) inamounts greater than about 50 wt % based on the total weight of theagent(s)/composition(s). In some examples, the water can be present inthe agent(s)/composition(s) in amounts from about 50 wt % to about 90 wt% based on the total weight of the agent(s)/composition(s). In otherexamples, the agent(s)/composition(s) can include water in an amount offrom about 60 wt % to about 90 wt % based on the total weight of theagent(s)/composition(s). In further examples, theagent(s)/composition(s) can include from about 70 wt % to about 85 wt %water.

To further illustrate the present disclosure, examples are given herein.It is to be understood that these examples are presented forillustrative reasons and are not to be construed as limiting the scopeof the present disclosure.

Examples

Table 1 below shows examples of five different types of polypropylenecopolymers and their performance during various tests—Gel PermeationChromatography (GPC), melt flow rate measurements (ASTM D1238), andzero-shear melt viscosity. The block copolymer polypropylene exhibitsmeasured values that are effective for use in efficiently creatingthree-dimensional printed parts with tensile strengths of greater thanabout 15 MPa.

Table 2 below shows examples of five different types of polypropylenecopolymers and their powder thermal characteristics for use inthree-dimensional printing.

Table 3 below shows examples of five different types of polypropylenecopolymers and their powder performance for use in three-dimensionalprinting.

TABLE 1 Measured Parameter Syndiotactic Isotactic PP Copolymer BlockRandom Isotactic PP + 10% Test Method Blend Copolymer copolymer PP talcGPC, 160° C., PS calibration, 57.692 57.854 22.520 19.992 49.3161,2,4-trichlorobenzene GPC, 145° C., PS calibration, 316.351 297.757219.517 213.563 395.388 1,2,4-trichlorobenzene GPC, 145° C., PScalibration, 653.962 549.86 472.922 533.38 1.501.8241,2,4-trichlorobenzene GPC, 145° C., PS calibration, 5.48 5.15 9.7510.68 8.02 1,2,4-trichlorobenzene ASTM D1238, 190° C., 2.16 kg 4.36 4.1716.06 12.14 3.18 ASTM D1238, 230° C., 2.16 kg 10.5 11.345 33.8 92.5575.6 Oscillary rheometer, plate-plate 1471 2283 861 176 4998 geometry,190° C., 0.1 Hz Oscillary rheometer, plate-plate 10205 5440 1692 6226278 geometry, melt T endset + 10° C., 0.1 Hz (Rotational rheometer,zero shear 12632 7163 1174 707 24672 viscosity, melt T endset + 10° C.)

TABLE 2 Syndiotactic Isotactic Measured PP Copolymer Block RandomIsotactic PP + 10% Parameter Unit Test Method Blend Copolymer copolymerPP talc Melt enthalpy ΔHm J/g ISO 11357, DSC, 60.78 52.3 47.93 88.0477.49 10° C./min, N2 gas Melt temperature ° C. ISO 11357, DSC, 125.2136.51 146.66 165.2 165.56 Tm 10° C./min, N2 gas Onset melt temp. ° C.ISO 11357, DSC, 104.59 117.68 128.67 156.48 152.03 Tm on 10° C./min, N2gas Enthalpy of J/g ISO 11357, DSC, 56.25 64.89 61.71 93.68 86.5crystallization ΔHc 10° C./min, N2 gas Crystallization ° C. ISO 11357-2,DSC, 88.68 99.36 105.05 120.12 120.88 temperature Tc 10° C./min, N2 gasOnset crystallization ° C. ISO 11357, DSC, 95.21 103.25 107.87 122.61123.42 temp. Tc on 10° C./min, N2 gas Processing window ° C. ISO 11357,DSC, 9.38 14.43 20.8 33.87 28.61 10° C./min, N2 gas Degree of % ISO11357, DSC, <34.34 <29.55 <27.08 49.74 43.5 crystallization 10° C./min,N2 gas Thermal Capacity J/g · ISO 11357, DSC, 2.3 1.99 2.09 2.40 2.10 K10° C./min, N2 gas Thermal W/m · ASTM E1225-13, 0.075 0.0652- 0.065 — —Conductivity K 60° C., fresh material 0.0756

TABLE 3 Syndiotactic Isotactic Measured PP Copolymer Block RandomIsotactic PP + 10% Parameter Unit Test Method Blend Copolymer copolymerPP talc Particle Size micron ISO 8130/13, dry 22.6 6.83 9.92 6.69 1.36Distribution D10 powder, distribution in number Particle Size micron ISO8130/13, dry 32.9 10.3 15 10 1.76 Distribution D50 powder, distributionin number Particle Size micron ISO 8130/13, dry 51.9 39.5 59.5 34.8 3.68Distribution D90 powder, distribution in number Polydispersity a.u. ISO8130/13, dry 1.1 1.30 1.30 1.4 1.7 powder, distribution in number Bulkdensity g/cm3 ASTM D1895, 500 taps 0.400 0.326 0.365 0.331 0.388 tapdensity g/cm3 ASTM D1895, 500 taps 0.563 0.388 0.413 0.418 0.458compression index % ASTM D1895, 500 taps 11.545 15.98 11.62 20.81 15.28Hausner ratio a.u. ASTM D1895, 500 taps 1.131 1.15 1.13 1.252 1.178 n1/2a.u. ASTM D1895, 500 taps 4.37 15 11.2 20.93 14.4 _(T) a.u. ASTM D1895,500 taps 10.06 19.97 16.67 22.8 15.3 avalanche energy J/g HP Procedure,23° C. 16.32 24.02 16.86 39.74 17.89 avalanche angle degree HPProcedure, 23° C. 47.2 52.4 49.5 56.8 56.8 avalanche slope J/g/rot HPProcedure, 23° C. −0.355 −5.485 1.333 −0.427 0.839 MDK percentage % HPmethod, 100 micron 0.852 0.500 0.450 0.635 0.668 of surface coveredlayer thickness, at RT Powder Particle J/g HP Procedure, DSC, 46.7 47.250.6 48.8 57.2 coalescence 10K/min Activation Energy

While several examples have been described in detail, it is to beunderstood that the disclosed examples may be modified. Therefore, theforegoing description is to be considered non-limiting.

Unless otherwise stated, any feature described hereinabove can becombined with any example or any other feature described herein.

In describing and claiming the examples disclosed herein, the singularforms “a,” “an,” and “the” include plural referents unless the contextclearly dictates otherwise.

It is to be understood that concentrations, amounts, and other numericaldata may be expressed or presented herein in range formats. It is to beunderstood that such range formats are used merely for convenience andbrevity and thus should be interpreted flexibly to include not just thenumerical values explicitly recited as the end points of the range, butalso to include all the individual numerical values or sub-rangesencompassed within that range as if each numerical value and sub-rangeis explicitly recited. As an illustration, a numerical range of “about 1wt % to about 5 wt %” should be interpreted to include not just theexplicitly recited values of about 1 wt % to about 5 wt %, but alsoinclude individual values and subranges within the indicated range.Thus, included in this numerical range are individual values such as 2,3.5, and 4 and sub-ranges such as from 1-3, from 2-4, and from 3-5, etc.This same applies to ranges reciting a single numerical value.

Reference throughout the specification to “one example,” “someexamples,” “another example,” “an example,” and so forth, means that aparticular element (e.g., feature, structure, and/or characteristic)described in connection with the example is included in at least oneexample described herein, and may or may not be present in otherexamples. In addition, it is to be understood that the describedelements for any example may be combined in any suitable manner in thevarious examples unless the context clearly dictates otherwise.

Unless otherwise stated, references herein to “wt %” of a component areto the weight of that component as a percentage of the whole compositioncomprising that component. For example, references herein to “wt %” of,for example, a solid material such as polyurethane(s) or colorant(s)dispersed in a liquid composition are to the weight percentage of thosesolids in the composition, and not to the amount of that solid as apercentage of the total non-volatile solids of the composition.

If a standard test is mentioned herein, unless otherwise stated, theversion of the test to be referred to is the most recent at the time offiling this patent application.

All amounts disclosed herein and in the examples below are in wt %unless indicated otherwise.

What is claimed is:
 1. A method of forming a polymeric powder buildmaterial composition for three-dimensional printing, the methodcomprising: mixing (A) a thermoplastic polymer powder composition,wherein the thermoplastic polymer powder composition comprises apolypropylene block copolymer made from polymerizing propylene andethylene or butylene or 1-pentene or 1-hexene or 1-octene or4-methyl-1-pentene and polypropylene homopolymers, (B) 0.1 to 1 wt %antioxidants based on the total weight of the thermoplastic polymerpowder composition, (C) 0.1 to 5 wt % flow aids based on the totalweight of the thermoplastic polymer powder composition, (D) 0.2 to 10 wt% of a surface modifying agent based on the total weight of thethermoplastic polymer powder composition, (E) 0.05 to 10 wt % antistaticagents based on the total weight of the thermoplastic polymer powdercomposition, (F) 2 to 40 wt % filler based on the total weight of thethermoplastic polymer powder composition, wherein the total of (A) to(F) is 100 wt %, to form the polymeric powder build materialcomposition.
 2. The method of claim 1, wherein the surface modifyingagent is present in an amount of from about 0.2 wt % to about 5 wt %based on the total weight of the thermoplastic polymer powdercomposition.
 3. The method of claim 1, wherein the filler is areinforcing material selected from the group consisting of glass beads,fumed silica, hollow glass beads, glass fibers, crushed glass, silicondioxide, aluminum oxide, calcium carbonate, hydrous aluminum silicate,ceramic fibers, silicon carbide fibers, alumina fibers, carbon fibers,polypropylene fibers, polyamide fibers, polyoxymethylene fibers,ultra-high molecular weight polyethylene fibers, polytetrafluoroethylenefibers, liquid crystal fibers, aramid fibers, and combinations thereof.4. The method of claim 1, wherein the filler is a flame retardingcompound selected from the group consisting of an alkali or earth alkalisulfonate, sulphonamide salt, perfluoroborate, halogenated compound andphosphorus-bearing organic compound, and combinations thereof.
 5. Themethod of claim 1, wherein the filler is an elastomeric materialselected from the group consisting of styrene butadiene styrene blockcopolymers, styrene-ethylene/butylene-styrene block copolymer,styrene-isoprene-styrene block copolymer, hydrogenatedstyrene-isoprene-styrene block copolymer, ethylene-propylene rubber, andcombinations thereof.
 6. A method of using the polymeric powder buildmaterial composition of claim 1 comprising: depositing a layer of thepolymeric powder build material on a build platform.
 7. The method ofclaim 1, wherein the 2 wt % to 40 wt % filler comprises 10 wt % to 40 wt% of the filler based on the total weight of the thermoplastic polymerpowder composition.
 8. The method of claim 1, wherein the 2 wt % to 40wt % filler comprises 10 wt % to 30 wt % of the filler based on thetotal weight of the thermoplastic polymer powder composition.
 9. Themethod of claim 1, wherein the mixing comprises dry blending using aprinter or a powder management station.
 10. A method forthree-dimensional printing comprising: depositing a layer of a polymericpowder build material on a build platform, the polymeric powder buildmaterial comprising a thermoplastic polymer powder composition, whereinthe thermoplastic polymer powder composition comprises: (A) apolypropylene block copolymer made from polymerizing propylene andethylene or butylene or 1-pentene or 1-hexene or 1-octene or4-methyl-1-pentene and polypropylene homopolymers, and (B) 0.2 to 10 wt%of a surface modifying agent based on the total weight of thethermoplastic polymer powder composition, based on a 3D object model,selectively applying a fusing agent to at least a portion of the layerof the polymeric powder build material, wherein the fusing agentcomprises at least one infrared absorbing compound; and exposing thepolymeric powder build material to radiation to fuse the at least theportion to form a layer of a 3D part.
 11. The method of claim 10,wherein the polymeric powder build material further comprises: (C) 0.1to 1 wt % antioxidants based on the total weight of the thermoplasticpolymer powder composition, (D) 0.1 to 5 wt % flow aids based on thetotal weight of the thermoplastic polymer powder composition, (E) 0.05to 5 wt % antistatic agents based on the total weight of thethermoplastic polymer powder composition, (F) 10 to 20 wt % filler basedon the total weight of the thermoplastic polymer powder composition,wherein the total of (a) to (f) is 100 wt %.
 12. The method of claim 10,wherein the polypropylene block copolymer comprises the followingparticle size distribution: D10: about 20 μm-about 45 μm; D50: about 50μm-about 85 μm; and D90: about 90 μm-about 140 μm.
 13. The method ofclaim 10, wherein the infrared absorbing compound is a near infraredabsorbing compound.
 14. The method of claim 13, wherein the nearinfrared absorbing compound is selected from the group consisting ofcarbon black, oxonol, squarylium, chalcogenopyrylarylidene,bis(chalcogenopyrylo)polymethine, bis(aminoaryl)polymethine,merocyanine, trinuclear cyanine, indene-crosslinked polymethine,oxyindolidine, iron complexes, quinoids, nickel-dithiolene complex,cyanine dyes, and combinations thereof.
 15. The method of claim 10further comprising: selectively applying a detailing agent on thepolymeric powder build material.
 16. A method of forming athree-dimensional printed part, the method comprising: depositing alayer of a polymeric powder build material comprising a thermoplasticpolymer powder composition, wherein the thermoplastic polymer powdercomposition comprises: (A) a polypropylene block copolymer made frompolymerizing propylene and ethylene or butylene or 1-pentene or 1-hexeneor 1-octene or 4-methyl-1-pentene and polypropylene homopolymers; and(B) 0.2 to 10 wt% of a surface modifying agent based on the total weightof the thermoplastic polymer powder composition, exposing the polymericpowder build material to heat to fuse the at least a portion of thelayer of the polymeric powder build material to form a layer of a 3Dpart.